//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17510 SUBJECT: GRB 150301A: Swift detection of a short burst or new SGR DATE: 15/03/01 01:26:16 GMT FROM: Scott Barthelmy at NASA/GSFC A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), D. N. Burrows (PSU), J. R. Cummings (NASA/UMBC), M. De Pasquale (INAF-IASFPA), L. M. Z. Hagen (PSU), J. A. Kennea (PSU), C. B. Markwardt (NASA/GSFC), A. Maselli (INAF-IASFPA), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 01:04:28 UT, the Swift Burst Alert Telescope (BAT) triggered and located a source which could be a short GRB or a new SGR (trigger=632995). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 244.286, -48.697, which is RA(J2000) = 16h 17m 09s Dec(J2000) = -48d 41' 48" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve shows a single peak structure with a duration of about 0.1 sec. The peak count rate was ~8500 counts/sec (15-350 keV), at ~0 sec after the trigger. The XRT began observing the field at 01:05:26.6 UT, 58.3 seconds after the BAT trigger. XRT found a bright, uncatalogued X-ray source located at RA, Dec 244.3047, -48.7131 which is equivalent to: RA(J2000) = +16h 17m 13.13s Dec(J2000) = -48d 42' 47.2" with an uncertainty of 5.0 arcseconds (radius, 90% containment). This location is 73 arcseconds from the BAT onboard position, within the BAT error circle. No event data are yet available to determine the column density using X-ray spectroscopy. UVOT took a finding chart exposure of 113 seconds with the White filter starting 65 seconds after the BAT trigger. No credible afterglow candidate has been found in the initial data products. The 2.7'x2.7' sub-image covers none of the XRT error circle. The coverage of the XRT error circle by the 8'x8' region for the list of sources generated on-board is uncertain because the large number of sources filled the available telemetry. The list of sources is typically complete to about 18 mag. No correction has been made for the large, but uncertain extinction expected. We note that this source is near the Galactic Plane and Bulge (lat = 1.36, lon = 334) and so this might be a previously-unknown Soft Gamma Repeater. The burst has significant emission above 100 keV, which is unusual, but not unprecedented, for an SGR. Further analysis of the full data set and continued observation is required to determine the nature of this source. Burst Advocate for this burst is A. Y. Lien (amy.y.lien AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17511 SUBJECT: GRB 150301A: Fermi GBM observation DATE: 15/03/01 05:25:53 GMT FROM: Valerie Connaughton at UAH/NSSTC Valerie Connaughton and Peter Jenke (UAH) and Adam Goldstein (NASA MSFC) report on behalf of the Fermi GBM Team: "At 01:04:28.65 UT on 01 March 2015, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 150301A (trigger 446864671 / 150301045) which was also detected by the Swift/BAT (Lien et al. 2015, GCN 17510). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is 105 degrees. The GBM light curve consists of a single peak about 50 ms in duration. The counts registered in the NaI detectors are strongly peaked in the 50 - 300 keV energy range typical for GRBs. From the quicklook data, the softness ratio for the event (20 - 100 keV / 100 - 500 keV) is 0.4 +/- 0.3, typical for fairly hard GRBs. By contrast, the corresponding softness ratios for recent triggers from SGR 1935+2154 and AXP 4U 0142+61 were 4.4 +/- 1.8, 3.4 +/- 1.0, and 2.2 +/- 0.4. The time-averaged spectrum from T0-0.016 s to T0+0.032 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -0.53 +/- 0.35 and the cutoff energy, parameterized as Epeak, is 185 +/- 49 keV. The event fluence (10-1000 keV) in this time interval is (1.2 +/- 0.2)E-07 erg/cm^2. The 16-msec peak photon flux measured starting from T0-0.016 s in the 10-1000 keV band is 29 +/- 4 ph/s/cm^2. The spectral characteristics of this burst are more like a GRB than an SGR. We think it is therefore unlikely that this event is a burst from a new SGR and conclude that it is, instead, a short GRB. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17513 SUBJECT: GRB 150301A: GROND Observations DATE: 15/03/01 14:29:55 GMT FROM: Corentin Delvaux at MPE M. Tanga, C. Delvaux, J. Greiner (all MPE Garching) and D. A. Kann (TLS Tautenburg) report on behalf of the GROND team: We observed the field of GRB 150301A (Swift trigger 632995; Lien et al., GCN #17510) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla Observatory (Chile). Observations started at 06:02 UT on 01-03-2015, 4.97 hrs after the GRB trigger. They were performed at an average seeing of 1.4" and at an average airmass of 1.5. We found two point sources within the 5.0" Swift-XRT error circle reported by Lien et al. (GCN #17510). The first source is at RA (J2000.0) = 16 h 17 m 13.08 s DEC (J2000.0) = -48d 42' 45.7" The second source is at RA (J2000.0) = 16 h 17 m 13.34 s DEC (J2000.0) = -48d 42' 49.7"  with an uncertainty of 0.3" in each coordinate for both sources. Based on the first 50 min of total exposures in g'r'i'z' and 40 min in JHK, we estimate the following preliminary magnitudes (all in AB system): For the first source: g' > 24.4 mag, r' > 24.5 mag, i' = 22.0 +/- 0.1 mag, z' = 21.0 +/- 0.3 mag, J = 18.8 +/- 0.2 mag, H = 18.3 +/- 0.2 mag, and K > 18.3 mag. For the second source: g' > 24.4 mag, r' > 24.5 mag, i' = 23.1 +/- 0.1 mag, z' = 22.2 +/- 0.1 mag, J = 19.6 +/- 0.3 mag, H = 19.1 +/- 0.4 mag, and K > 18.3 mag. Both objects appear to be constant over the duration of our observation. Therefore we suppose they are not related to the burst. We note the field is crowded. We also notice the presence of a bright star (~14 mag) west of the Swift-XRT error circle covering around 10% of the encircled region. Given magnitudes are calibrated against GROND zeropoints as well as 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=3.31 mag in the direction of the burst (Schlafly & Finkbeiner 2011). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17515 SUBJECT: GRB 150301B: Swift detection of a burst with an optical afterglow DATE: 15/03/01 19:50:01 GMT FROM: David Palmer at LANL A. Y. Lien (GSFC/UMBC), D. N. Burrows (PSU), M. M. Chester (PSU), J. R. Cummings (NASA/UMBC), M. De Pasquale (INAF-IASFPA), A. Maselli (INAF-IASFPA), K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU) report on behalf of the Swift Team: At 19:38:04 UT, the Swift Burst Alert Telescope (BAT) triggered and located GRB 150301B (trigger=633180). Swift slewed immediately to the burst. The BAT on-board calculated location is RA, Dec 89.157, -57.977 which is RA(J2000) = 05h 56m 38s Dec(J2000) = -57d 58' 37" with an uncertainty of 3 arcmin (radius, 90% containment, including systematic uncertainty). The BAT light curve showed a single-peaked structure with a duration of about 20 sec. The peak count rate was ~4000 counts/sec (15-350 keV), at ~1 sec after the trigger. The XRT began observing the field at 19:39:26.4 UT, 82.4 seconds after the BAT trigger. Using promptly downlinked data we find an uncatalogued X-ray source located at RA, Dec 89.16636, -57.97051 which is equivalent to: RA(J2000) = 05h 56m 39.93s Dec(J2000) = -57d 58' 13.8" with an uncertainty of 3.6 arcseconds (radius, 90% containment). This location is 29 arcseconds from the BAT onboard position, within the BAT error circle. This position may be improved as more data are received; the latest position is available at http://www.swift.ac.uk/sper. A power-law fit to a spectrum formed from promptly downlinked event data gives a column density consistent with the Galactic value of 6.16 x 10^20 cm^-2 (Willingale et al. 2013). UVOT took a finding chart exposure of 150 seconds with the White filter starting 85 seconds after the BAT trigger. There is a candidate afterglow in the rapidly available 2.7'x2.7' sub-image at RA(J2000) = 05:56:39.86 = 89.16608 DEC(J2000) = -57:58:10.4 = -57.96956 with a 90%-confidence error radius of about 0.61 arc sec. This position is 31.9 arc sec. from the center of the BAT error circle. The estimated magnitude is 16.22 with a 1-sigma error of about 0.14. No correction has been made for the expected extinction corresponding to E(B-V) of 0.08. Burst Advocate for this burst is A. Y. Lien (amy.y.lien AT nasa.gov). Please contact the BA by email if you require additional information regarding Swift followup of this burst. In extremely urgent cases, after trying the Burst Advocate, you can contact the Swift PI by phone (see Swift TOO web site for information: http://www.swift.psu.edu/too.html.) //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17516 SUBJECT: GRB 150301C : (Swift trigger 633105) Swift observations DATE: 15/03/01 20:31:02 GMT FROM: Jay R. Cummings at NASA/GSFC/Swift M. Stamatikos (OSU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (CPI), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), J. Tueller (GSFC), T. N. Ukwatta (LANL), F. Marshall (NASA/GSFC), D. Malesani (DARK/NBI), L. Hagen (PSU), M. de Pasquale (INAF-IASFPA), A. Maselli (INAF-IASFPA), D.N. Burrows (PSU), K. Page (U. Leicester), N. P. M. Kuin (UCL-MSSL) Using the data set from T-60 to T+243 sec from the recent telemetry downlink, we report further analysis of possible GRB 150301C (trigger #633105) (Lien, et al., GCN Circ. 17512). The BAT ground-calculated position is RA, Dec = 11.319, 41.861 deg which is RA(J2000) = 00h 45m 16.6s Dec(J2000) = +41d 51' 40.0" with an uncertainty of 2.2 arcmin, (radius, sys+stat, 90% containment). The significance in the BAT image was 10.1, so we are sure that this was a real astrophysical source. The partial coding was 69%. The location is well within the visible light of M31. A more distant galaxy, [JSD2012] 170, which has a size of 0.11 arcmin, is within the BAT error circle. In 1.9 ks of data, the Swift XRT found only a single very weak source (2.8 sigma), consistent with the position of a known source within the BAT error circle, [PFH2005] 622, with a count rate of (5.3+/-1.9) x 10^-03 c/s. We cannot state whether there is any variability of this source at this time. The XRT position of this source is: RA (J2000) 00h 45m 14.4s Dec (J2000) +41d 50' 37.7" The BAT mask-weighted light curve shows a single weak FRED peak. T90 (15-350 keV) is 14 +- 3 sec (estimated error including systematics). The time-averaged BAT spectrum from T-0.6 to T+15.0 sec is best fit by a power- law model with an exponential cutoff. The power law index of the time-averaged spectrum is poorly defined but is nominally -0.8 +- 2. The peak energy is 38 +- 7 keV. The fluence in the 15-150 keV band is 2.1 +- 0.4 x 10^-07 erg/cm2. The 1-sec peak photon flux measured from T+1.32 sec in the 15-150 keV band is 0.6 +- 0.2 ph/cm2/sec. A simple power-law fit has a photon index of 1.96 +- 0.25. All the quoted errors are at the 90% confidence level. If this source was in M31, its isotropic energy output was 1.5 x 10^43 ergs in 15.6 seconds in the range 15-150 keV. It is very possible, given the softness of the source, that this is a non-GRB in M31. The color:duration is within the distribution of long GRBs. No XRT source was seen in the initial observations, whereas we might expect most sources in M31 bright enough to be seen in BAT would be very bright in XRT. Therefore the source is likely to be highly absorbed. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/633105/BA/ The Swift/UVOT began settled observations of the field 102 s after the BAT trigger (Lien et al., GCN Circ. 17512). No new source within the BAT error circle is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 102 4151 369 >20.39 v 592 4562 216 >18.55 b 518 5241 96 >19.08 u 261 5177 461 >19.69 uvw1 641 4973 216 >19.27 uvm2 617 4768 216 >19.20 uvw2 568 4357 216 >19.41 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.06 in the direction of the burst (Schlegel et al. 1998). Further Swift observations are planned. [GCN OPS NOTE(01mar15): Per author's request, the affiliation was corrected for KP.] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17517 SUBJECT: GRB 150301A: Swift-XRT refined Analysis DATE: 15/03/01 20:45:59 GMT FROM: Phil Evans at U of Leicester M. de Pasquale (INAF-IASFPA), A. Maselli (INAF-IASFPA), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), P.A. Evans (U. Leicester), A. Amaral-Rogers (U. Leicester), J.P. Osborne (U. Leicester), A. Melandri (INAF-OAB) and A.Y. Lien report on behalf of the Swift-XRT team: We have analysed 147 s of XRT data for GRB 150301A (Lien et al. GCN Circ. 17510), from 50 s to 43.7 ks after the BAT trigger. The data are entirely in Windowed Timing (WT) mode (the first 6 s were taken while Swift was slewing). The light curve can be modelled with an initial power-law decay with an index of alpha=0.53 (+0.18, -0.59), followed by a break at T+112 s to an alpha of 2.6 (+0.6, -0.7). A spectrum formed from the WT mode data can be fitted with an absorbed power-law with a photon spectral index of 1.71 (+0.21, -0.20). The best-fitting absorption column is 5.6 (+/-0.7) x 10^22 cm^-2, in excess of the Galactic value of 1.3 x 10^22 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 9.1 x 10^-11 (2.0 x 10^-10) erg cm^-2 count^-1. A summary of the WT-mode spectrum is thus: Total column: 5.6 (+/-0.7) x 10^22 cm^-2 Galactic foreground: 1.3 x 10^22 cm^-2 Excess significance: 10.5 sigma Photon index: 1.71 (+0.21, -0.20) If the light curve continues to decay with a power-law decay index of 2.6, the count rate at T+24 hours will be 9.7 x 10^-7 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.8 x 10^-17 (1.9 x 10^-16) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00632995. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17518 SUBJECT: GRB 150301B: MASTER early OT detection DATE: 15/03/01 20:51:41 GMT FROM: Vladimir Lipunov at Moscow State U/Krylov Obs D.Buckley, S. Potter, A.Kniazev, M.Kotze South African Astronomical Observatory E. Gorbovskoy, V. Lipunov, V.Kornilov, N.Tyurina, P.Balanutsa, A.Kuznetsov, V.V.Chazov, D.Kuvshinov, Lomonosov Moscow State University, Sternberg Astronomical Institute, Moscow State University V.Yurkov, Yu.Sergienko, D.Varda, E.Sinyakov Blagoveschensk Educational State University, Blagoveschensk A. Tlatov, A.V. Parhomenko, D. Dormidontov, V.Sennik Kislovodsk Solar Station of the Pulkovo Observatory V.Krushinsky, I.Zalozhnih, A. Popov Ural Federal University, Yekaterinburg, Kourovka Hugo Levato and Carlos Saffe Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE) Claudio Mallamaci, Carlos Lopez and Federico Podest Observatorio Astronomico Felix Aguilar (OAFA) MASTER II robotic telescope (MASTER-Net: http://observ.pereplet.ru) located in SAAO was pointed to the GRB150301.82 (Lien et al, GCN 17515) 60 sec after notice time and 79 sec after trigger time at 2015-03-01 19:39:23 UT in two polarizations. On our first (10s exposure) set we found 1 optical transient within SWIFT error-box (ra=05 56 37 dec=-57 58 35 r=0.050000). T_start RA DEC Exp unfiltered s magnitude 2015-03-01 19:39:23 79.0 05h 56m 39.94s -57d 58m 10.0s 15.3 The error is about 0.5 arcsec. This position is coincidet with UVOT data. We detected OT before maximum brightness. The 5-sigma upper limit has been about 16.8 mag . The telegram is generated automatically. We have number of the images after maximum in two polarizations. The reduction is continuated. The message may be cited. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17519 SUBJECT: GRB 150301A: Swift-BAT refined analysis DATE: 15/03/01 22:13:47 GMT FROM: Amy Lien at GSFC T. Sakamoto (AGU), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), M. Stamatikos (OSU), J. Tueller (GSFC), T. N. Ukwatta (LANL) (i.e. the Swift-BAT team): Using the data set from T-210 to T+962 sec from the recent telemetry downlink, we report further analysis of BAT GRB 150301A (trigger #632995) (Lien, et al., GCN Circ. 17510). The BAT ground-calculated position is RA, Dec = 244.281, -48.732 deg which is RA(J2000) = 16h 17m 07.5s Dec(J2000) = -48d 43' 56.2" with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment). The partial coding was 96%. The mask-weighted light curve shows a single short FRED peak that starts at ~ T0 and ends at ~ T+0.5 s. T90 (15-350 keV) is 0.48 +- 0.14 sec (estimated error including systematics). The time-averaged spectrum from T+0.00 to T+0.56 sec fit by a simple power-law model has a power law index of 1.44 +- 0.23 (chi squared 54.10 for 57 d.o.f.). The fluence in the 15-150 keV band is 7.4 +- 1.0 x 10^-8 erg/cm2. The 1-sec peak photon flux measured from T-0.22 sec in the 15-150 keV band is 1.0 +- 0.2 ph/cm2/sec. A single blackbody fit to the time-averaged spectrum shows a blackbody temperature of 15.11 +- 2.92 keV (chi squared 74.66 for 57 d.o.f.). A thermal bremsstrahlung model fit shows the temperature of 199.36 keV (chi squared 55.72 for 57 d.o.f.). Despite being near the Galactic Plane and Bulge (lat = 1.36, lon = 334), both the fast-decaying XRT light curve and Fermi/GBM observation (Connaughton et al., GCN Circ. 17511) suggests that this source is more likely to be a short GRB than a SGR. In addition, there are no other BAT detections of this source before or since this trigger. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/632995/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17520 SUBJECT: GRB 150301B: Enhanced Swift-XRT position DATE: 15/03/01 22:44:01 GMT FROM: Phil Evans at U of Leicester P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) report on behalf of the Swift-XRT team. Using 386 s of XRT Photon Counting mode data and 1 UVOT images for GRB 150301B, we find an astrometrically corrected X-ray position (using the XRT-UVOT alignment and matching UVOT field sources to the USNO-B1 catalogue): RA, Dec = 89.16660, -57.96950 which is equivalent to: RA (J2000): 05h 56m 39.98s Dec (J2000): -57d 58' 10.2" with an uncertainty of 1.8 arcsec (radius, 90% confidence). This position may be improved as more data are received. The latest position can be viewed at http://www.swift.ac.uk/xrt_positions. Position enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans et al. (2009, MNRAS, 397, 1177). This circular was automatically generated, and is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17521 SUBJECT: GRB 150301A: Swift/UVOT Upper Limits DATE: 15/03/02 00:59:47 GMT FROM: Lea Hagen at PSU L. M. Z. Hagen (PSU) and A. Y. Lien (GSFC/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 150301A 66 s after the BAT trigger (Lien et al., GCN Circ. 17510). No optical afterglow consistent with the XRT position (Lien et al. GCN Circ. 17510) or GROND candidates (Tanga et al. GCN Circ. 17513) is detected in the initial UVOT exposures. Preliminary 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 66 4931 306 >21.08 v 5143 5343 196 >19.40 b 4526 10879 750 >21.16 u 4321 5926 362 >20.08 uvw1 5553 5752 196 >19.61 uvm2 5347 5547 196 >19.40 uvw2 4937 5137 196 >19.82 The magnitudes in the table are not corrected for the substantial Galactic extinction due to the reddening of E(B-V) = 3.84 in the direction of the burst (Schlegel et al. 1998). We note that the photometry is likely affected by a nearby bright foreground star. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17522 SUBJECT: GRB 150301B: GROND afterglow observations DATE: 15/03/02 01:55:37 GMT FROM: Alexander Kann at TLS Tautenburg D. A. Kann (TLS Tautenburg), C. Delvaux and J. Greiner (both MPE Garching) report on behalf of the GROND team: We observed the field of GRB 150301B (Swift trigger 633180; Lien et al., GCN #17515) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla Observatory (Chile). Observations started at 00:09 UT on 2015-03-02, 4.5 hrs after the GRB trigger. They were performed at an average seeing of 1".0 and at an average airmass of 1.1. We detect the optical afterglow candidate reported by Lien et al. (GCN #17515) and Buckley et al. (GCN #17518). Based on 7.7 min of total exposure time in g'r'i'z' and 8.0 min in JHK, centered 5 hrs after the GRB, we estimate the following preliminary magnitudes (all in AB system): g' = 21.7 +/- 0.2 mag, r' = 21.4 +/- 0.1 mag, i' = 21.2 +/- 0.1 mag, z' = 21.0 +/- 0.1 mag, J = 20.5 +/- 0.3 mag, H = 20.6 +/- 0.4 mag, and K > 17.9 mag. Given magnitudes are calibrated against GROND zeropoints (g'r'i'z') as well as 2MASS field stars and are not corrected for the expected Galactic foreground extinction corresponding to a reddening of E_(B-V)=0.08 mag in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17523 SUBJECT: GRB 150301B: X-shooter spectroscopy DATE: 15/03/02 02:07:10 GMT FROM: Antonio de Ugarte Postigo at IAA-CSIC A. de Ugarte Postigo (IAA-CSIC, DARK/NBI), T. Kruehler (ESO), H. Flores (GEPI/Obs. de Paris), and J.P.U. Fynbo (DARK/NBI) report on behalf of a larger collaboration: We observed the afterglow of GRB 150301B (Lien et al. GCN 17515, Buckley et al. GCN 17518, Kann et al. GCN 17522) with X-shooter at the Very Large Telescope (Paranal Observatory, Chile). Observations started at 00:45 UT (5.12 hr after the burst), and consisted of 6x600 s exposures covering the spectral range between 3 000 and 18 000 Angstroms. In the acquisition image the afterglow is detected with R(Vega) = 21.0 mag, as compared to stars of the USNOB-1.0 catalogue. On a preliminary reduction we detect a weak continuum with absorption features of FeII, MgII and MgI at a common redshift of z = 1.5169, which we suggest as the redshift of the GRB. We acknowledge the excellent support provided by Paranal staff, and in particular Andrea Mehner, Tayyaba Zafar, and Marcelo Lopez. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17524 SUBJECT: GRB 150301B: Swift-BAT refined analysis DATE: 15/03/02 05:24:04 GMT FROM: Amy Lien at GSFC T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC), W. H. Baumgartner (GSFC/UMBC), J. R. Cummings (GSFC/UMBC), N. Gehrels (GSFC), H. A. Krimm (GSFC/USRA), A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC), D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU), J. Tueller (GSFC), (i.e. the Swift-BAT team): Using the data set from T-60 to T+243 sec from the recent telemetry downlink, we report further analysis of BAT GRB 150301B (trigger #633180) (Lien, et al., GCN Circ. 17515). The BAT ground-calculated position is RA, Dec = 89.159, -57.969 deg which is RA(J2000) = 05h 56m 38.3s Dec(J2000) = -57d 58' 07.8" with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment). The partial coding was 62%. The mask-weighted light curve shows a single-peaked structure that starts at ~ T0, peaks at ~ T+3 s, and ends at ~ T+16 s. T90 (15-350 keV) is 12.44 +- 1.49 sec (estimated error including systematics). The time-averaged spectrum from T-0.34 to T+15.62 sec is best fit by a simple power-law model. The power law index of the time-averaged spectrum is 1.46 +- 0.07. The fluence in the 15-150 keV band is 1.8 +- 0.1 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from T+3.65 sec in the 15-150 keV band is 3.0 +- 0.2 ph/cm2/sec. All the quoted errors are at the 90% confidence level. The results of the batgrbproduct analysis are available at http://gcn.gsfc.nasa.gov/notices_s/633180/BA/ //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17525 SUBJECT: GRB 150301B: Fermi GBM detection DATE: 15/03/02 05:26:50 GMT FROM: Eric Burns at U of Alabama E. Burns (UAH) and C. Meegan (UAH) report on behalf of the Fermi GBM Team: "At 19:38:04.51 UT on 01 March 2015, the Fermi Gamma-Ray Burst Monitor triggered and located GRB 150301B (trigger 446931487/150301818) which was also detected by the Swift/BAT (Lien et al. 2015, GCN 17515). The GBM on-ground location is consistent with the Swift position. The angle from the Fermi LAT boresight is 39 degrees. The GBM light curve consists of one main peak with a duration (T90) of about 13 s (50-300 keV). The time-averaged spectrum from T0-2.560 s to T0+13.824 s is best fit by a power law function with an exponential high-energy cutoff. The power law index is -1.2 +/- 0.1 and the cutoff energy, parameterized as Epeak, is 256 +/- 32 keV. A Band function fits the spectrum equally well with Epeak= 180 +/- 38 keV, alpha = -1.1 +/- 0.1 and beta = -2.0 +/- 0.2. The event fluence (10-1000 keV) in this time interval is (4.4 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured starting from T0+2.560 s in the 10-1000 keV band is 4.5 +/- 0.2 ph/s/cm^2. The spectral analysis results presented above are preliminary; final results will be published in the GBM GRB Catalog." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17530 SUBJECT: GRB 150301B: LCOGT-Sutherland observations DATE: 15/03/02 09:00:17 GMT FROM: Cristiano Guidorzi at Ferrara U,Italy C. Guidorzi (U. Ferrara), J. Japelj, A. Gomboc (U. Ljubljana), C.G. Mundell (U. Bath), on behalf of a large collaboration report: One of the Las Cumbres Observatory 1-m telescopes in Sutherland (South Africa) began observing Swift and Fermi GRB 150301B (Lien et al. GCN 17515; Burns et al. GCN 17525) on March 01 at 20:07:30 UT, i.e. ~29.4 minutes after the BAT trigger with the r', i', and g' filters. We detect the optical afterglow (Lien et al. GCN 17515; Buckley et al. GCN 7518; Kann et al. GCN 17522; de Ugarte Postigo et al. GCN 17523) with the following magnitudes: Mid time from Total Exp Filter Magnitude trigger (min) (s) ------------------------------------------------- 37.7 360 r' 18.85 +- 0.25 42.3 360 i' 18.5 +- 0.3 ------------------------------------------------- Values have been calibrated against nearby USNOB-1 stars (R2 and I). Compared with earlier (Buckley et el.) and later (Kann et al.) observations, our values suggest an overall power-law decay index ~1. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17531 SUBJECT: GRB 150301B: Swift/UVOT Observations DATE: 15/03/02 14:28:45 GMT FROM: Margaret Chester at PSU M. M. Chester (PSU) and A. Y. Lien (GSFC/UMBC) report on behalf of the Swift/UVOT team: The Swift/UVOT began settled observations of the field of GRB 150301B 86 s after the BAT trigger (Lien et al., GCN Circ. 17515). A fading source consistent with the XRT position (Evans et al. GCN Circ. 17520) and the optical transient reported by Buckley et al. (GCN Circ. 17518) is detected in the initial UVOT exposures. The preliminary UVOT position is: RA (J2000) = 05:56:39.89 = 89.16622 (deg.) Dec (J2000) = -57:58:10.4 = -57.96955 (deg.) with an estimated uncertainty of 0.42 arc sec. (radius, 90% confidence). Preliminary detections and 3-sigma upper limits for the White finding chart and subsequent exposures using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white_FC 86 236 147 16.2 +/- 0.1 white 3986 4121 133 >20.2 v 5833 6033 197 >19.7 b 3782 3982 197 >19.6 u 298 543 241 17.1 +/- 0.1 w1 6243 10068 579 >19.9 m2 6038 6237 197 >19.8 w2 5628 16054 963 >21.6 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.08 in the direction of the burst (Schlegel et al. 1998). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17533 SUBJECT: GRB 150301B: Swift-XRT refined Analysis DATE: 15/03/02 19:50:04 GMT FROM: Phil Evans at U of Leicester A. Maselli (INAF-IASFPA), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), J.A. Kennea (PSU), A. Amaral-Rogers (U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB) and A.Y. Lien report on behalf of the Swift-XRT team: We have analysed 5.7 ks of XRT data for GRB 150301B (Lien et al. GCN Circ. 17515), from 67 s to 69.5 ks after the BAT trigger. The data comprise 67 s in Windowed Timing (WT) mode (the first 9 s were taken while Swift was slewing) with the remainder in Photon Counting (PC) mode. The enhanced XRT position for this burst was given by Evans et al. (GCN Circ. 17520). The light curve can be modelled with a power-law decay with a decay index of alpha=1.11 (+0.05, -0.04). A spectrum formed from the PC mode data can be fitted with an absorbed power-law with a photon spectral index of 1.81 (+0.18, -0.10). The best-fitting absorption column is consistent with the Galactic value of 6.2 x 10^20 cm^-2 (Willingale et al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor deduced from this spectrum is 3.7 x 10^-11 (4.2 x 10^-11) erg cm^-2 count^-1. A summary of the PC-mode spectrum is thus: Galactic foreground: 6.2 x 10^20 cm^-2 Intrinsic column: 6 (+/-14) x 10^20 cm^-2 at z=1.5169 Photon index: 1.81 (+0.18, -0.10) If the light curve continues to decay with a power-law decay index of 1.11, the count rate at T+24 hours will be 3.3 x 10^-3 count s^-1, corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x 10^-13 (1.4 x 10^-13) erg cm^-2 s^-1. The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00633180. This circular is an official product of the Swift-XRT team. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17536 SUBJECT: GRB 150301C: XRT detection of a potential counterpart of BAT trigger 633105 DATE: 15/03/02 23:19:36 GMT FROM: Amy Lien at GSFC Phil Evans (U. Leicester) , Alessandro Maselli (INAF-IASFPA), David Burrows (PSU), Sergio Campana (INAF-OAB), Neil Gehrels (GSFC), Jamie Kennea (PSU), Amy Lien (GSFC/UMBC), Lea Hagen (PSU), Daniele Malesani (DARK/NBI), Frank Marshall (GSFC), Julian Osborne (U. Leicester), Kim L. Page (U Leicester), Massimiliano De Pasquale (INAF-IASFPA) report on behalf of the Swift team: We report further XRT observations of the highly unusual transient or GRB detected by BAT on March 1 ( trigger 633105 or GRB150301C; Lien et al., GCN Circ 17512; Stamatikos et al., GCN Circ 17516). It lasted about 20 seconds in BAT and has a location in M31, but had very weak X-ray emission. The XRT found a single source within the BAT error circle, which is coincident with the known X-ray source [PFH2005] 622. This source was previously reported in an XMM-Newton survey of M31 (Pietsch et al., A&A, 434, 483, 2005), and was classified as a "hard" source based on the hardness ratio (see definition in Pietsch et al. 2005). The paper suggests that these "hard" sources may be X-ray binaries, Crab-like SNRs, or AGNs. Using the faint-source-optimised detection system from the 1SXPS catalogue (Evans et al., ApJS 210, 8, 2014), the XRT source is detected with a likelihood of 18.3 in the first observation of the BAT error region. This corresponds to a "Good"-flagged object, i.e. a >3-sigma detection. The refined XRT position is RA,Dec = 11.3107, +41.8431 degrees which corresponds to RA (J2000): 00h 45m 14.57s Dec (J2000): +41d 50' 35.1" with an uncertainty of 5.7 arcsec (radius, 90% confidence). This is 4 arcsec from the catalogued position of [PFH2005] 622, which is at RA=00h 45m 14.87,Dec=+41d 50' 33'' with an uncertainty of 1.5 arcsec. Hence, the XRT position is consistent with the position of [PFH2005] 622. During the first XRT observation, starting at T0+105s and lasting 1.9 ks, the source is detected with a count-rate of 6.0 (+2.3, -1.8) x10^-3 ct/sec. In the subsequent observations, from T0+44.9 ks and totalling 6ks exposure, the source is undetected, with an upper limit of 1.2 x10^-3 ct/sec, consistent with fading. Swift-XRT has previously observed this location for a total of ~4ks, corresponding to "Stacked image 7598" in the 1SXPS catalogue. The source was not detected in this dataset, with an upper limit of 2.2x10^-3 ct/sec, significantly below the level at which we have detected it in this observation. Additionally, XMM-Newton observations (Pietsch et al., 2005) detected this X-ray source in 2005 with a flux of 6.9x10^-15 erg/cm^2/s. The peak rate in our observations corresponds to ~2x10^-13 erg/cm^2/s, i.e. ~35 times brighter than the XMM detection. At the distance of M31, these fluxes correspond to a luminosity of ~5x10^35 erg/s (0.2-4.5 keV) in the XMM-Newton observations, and ~1.4x10^37 erg/s (0.3-10 keV) in the XRT observations. For comparison, the average luminosity in BAT at this distance was 1.25x10^42 erg/s in 15-150 keV (Stamatikos et al., GCN Circ 17516). We therefore conclude that XRT has detected a bursting source that is likely the counterpart to BAT trigger 633105. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17541 SUBJECT: Trigger 633105 (aka GRB150301C): Swift/UVOT Observations of XRT Counterpart DATE: 15/03/04 03:16:06 GMT FROM: Lea Hagen at PSU L. M. Z. Hagen (PSU) and A. Y. Lien (GSFC/UMBC) report on behalf of the Swift/UVOT team: A point source is detected by UVOT that is consistent with the XRT counterpart and 2.5 arcsec from the XMM-Newton source discussed in Evans et al. (GCN Circ. 17536). This source is also seen in archival DSS imaging. It is unclear if this is the same object detected by XRT or a serendipitous source. Given how crowded the field is, it is also likely that the UVOT source is comprised of multiple individual sources. The coordinates of the UVOT source are RA(J2000) = 00:45:14.76 = 11.31150 DEC(J2000) = +41:50:35.2 = 41.84311 Preliminary detections and 3-sigma upper limits using the UVOT photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the available exposures are: Filter T_start(s) T_stop(s) Exp(s) Mag white 102 4151 369 19.22+-0.13 v 592 4562 216 >18.53 b 518 5241 96 >19.08 u 261 5177 461 18.60+-0.15 uvw1 641 79666 5117 18.64+-0.05 uvm2 617 45953 1237 18.94+-0.13 uvw2 568 4357 216 18.99+-0.27 The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.06 in the direction of the source (Schlegel et al. 1998). This field has also been observed previously by UVOT as part of a different observing campaign, primarily in 2013 and 2014. The stacked images have the following detections: Filter Exp(s) Mag v 1406 19.04+-0.19 b 1445 19.77+-0.15 u 27521 18.65+-0.03 uvw1 52236 18.57+-0.02 uvm2 58908 18.65+-0.03 uvw2 65719 18.61+-0.02 These indicate possible variability of the source, but further analysis will be required to confirm this. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17543 SUBJECT: BAT trigger 633105 (GRB 150301C): NOT r-band upper limit DATE: 15/03/04 22:05:01 GMT FROM: Zach Cano at U of Iceland Z. Cano (Univ. Iceland), D. Malesani, J. P. U. Fynbo (DARK/NBI), A. de Ugarte Postigo (IAA/CSIC and DARK/NBI), N. R. Tanvir (Univ. Leicester), P. Jakobsson (Univ. Iceland), M. Saajasto, T. Pursimo (NOT), report on behalf of a larger collaboration: We observed the field of BAT trigger 633105 (Lien et al., GCN Circ. 17512) with the 2.5-m Nordic Optical Telescope (NOT) equipped with ALFOSC on 01-Mar-2015 and 03-Mar-2015, obtaining 6x300 s of SDSS r-band exposures in each epoch. The mid exposure times of our observations correspond to +0.60 and +2.59 days from the initial trigger, respectively. Consistent with the X-ray position of the known source [PFH2005] 622 (thought to be associated with the gamma-ray transient; Evans et al., GCN Circ. 17536), we detect one object at coordinates: RA = 00:45:14.80 Dec = +41:50:32.35 Its magnitude is R = 22.7 +- 0.1 (using a USNO-A2.0 star in the field for calibration). Two more objects are also detected in close proximity of the XMM position (Pietsch et al. 2005, A&A, 434, 483), and potentially consistent with it, including the source seen by UVOT by Hagen & Lien (GCN 17541), which appears to be quite blue (it has R = 22.3 +- 0.1 in our image). We carried out digital image subtraction between our two images, where we subtracted the first epoch from the second by using an adaptation of the ISIS software. In our difference image we do not detect any residual flux at the combined XRT and XMM location, down to an upper limit of R > 23.2. All objects seen in the NOT image are also apparent in the deep, archival data from the PAndAS survey (McConnachie et al. 2009, Nature, 461, 66), which also reveals a few more, fainter objects in the close proximity of the XMM position. No object seems to have varied significantly. A gif animation of the two epochs of NOT imaging, and the difference image, can be retrieved from: http://www.astro.ku.dk/~malesani/GRB/150301C/subtraction.gif A comparison image of the NOT image from 01-Mar-2015 and the PAndAS image can be found at: http://www.astro.ku.dk/~malesani/GRB/150301C/comparison_NOT_PAndAS.png //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17544 SUBJECT: Further X-ray observations of Swift J0045.2+4151 (aka Sw J0045 aka GRB 150301C aka [PFH2005] 622) DATE: 15/03/04 23:07:43 GMT FROM: Amy Lien at GSFC Alessandro Maselli (INAF-IASFPA), Phil Evans (U. Leicester), David Burrows (PSU), Sergio Campana (INAF-OAB), Neil Gehrels (GSFC), Jamie Kennea (PSU), Amy Lien (GSFC/UMBC), Daniele Malesani (DARK/NBI), Craig. B. Markwardt (GSFC), Frank Marshall (GSFC), Julian Osborne (U. Leicester), David. M. Palmer (LANL), Kim L. Page (U Leicester), Rhaana L. C. Starling (U Leicester) report on behalf of the Swift team: Swift continues to observe the field of BAT trigger 633105 (aka GRB 150301C) with sky location in M31. To avoid further naming confusion, this object will be referred as Swift J0045.2+4151 hereafter. The XRT continues to detect only a single source within the BAT error circle at a position coincident with the previously known XMM-Newton source, [PFH2005] 622 (Pietsch et al. 2005). For the rest of this circular we assume that the X-rays detected by XRT are from [PFH2005] 622. The XRT has acquired four observations so far. The source (which we presume is [PFH2005] 622) was detected in the first snapshot, (T0+107s to T0+720s), in which we detect 8 events in 614 seconds, with a mean background expectation of 0.34 counts. This results in a rate of 1.48 (+0.6, -0.5) e-2 counts/s (1 sigma errors). In the 2nd epoch (T0+4 ks to T0+80 ks), we detect 3 events in 7.2 ks, with an expected background of 1.25 events, giving a 3 sigma upper limit of < 0.002 counts/s. In the 3rd epoch (T0+171 ks to T0+206 ks), we find 5 events in 4.8 ks with a mean background expectation of 0.64 events, giving a 3 sigma detection of 1.2 (+0.8, -0.6) e-3 counts/s (1 sigma errors). All measurements use a source radius of 9 pixels (21 arcseconds), a background measurement from an annulus around the source region, and the Bayesian method of Kraft, Burrows, and Nousek (1991, ApJ, 374, 344) to obtain the 1-sigma confidence intervals (for detections) or 3-sigma upper limits (for non-detections). Therefore, after a detection in the initial XRT observation, the source faded below the XRT detection limit and may have brightened again in the 3rd epoch. We cannot conclude firmly at this point whether the source [PFH2005] 622 is associated with the BAT trigger or not. More observations at all wavelengths are encouraged. A table and a light curve that summarize current XRT observations of [PFH2005] 622 are available at: http://swift.gsfc.nasa.gov/results/BATbursts/633105/xrt/atel_20150304.html [GCN OPS NOTE(05mar15), Per author's request, the last line in the 5th paragraph was changed from "the 3 sigma confidence regions and upper limits." to "the 1-sigma confidence intervals (for detections) or 3-sigma upper limits (for non-detections).". And the places in the 2nd & 4th paragraphs that said "(1 sigma errors)" were changed to "(1 sigma errors)".] //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17545 SUBJECT: GRB 150301C: VLA Observations DATE: 15/03/04 23:18:10 GMT FROM: Tanmoy Laskar at Harvard U T. Laskar, E. Berger (Harvard) and D. Fox (PSU) report on behalf of a larger collaboration: "We observed GRB 150301C (Lien et al; GCN 17512) with the VLA beginning on 2015 March 04.03 UT (2.77 days after the burst) at a mean frequency of 9.8 GHz. No radio counterpart is detected in the 90-minute observation within the XRT error circle (Evans et al; GCN 17536) to a 3 sigma upper limit of 18 uJy. The 90-minute observation covers the full BAT error circle and does not contain any radio source brighter than the NVSS flux limit. Well-detected sources fainter than the NVSS limit have been identified for possible future monitoring. We thank the VLA staff for scheduling and obtaining these observations." //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 17549 SUBJECT: Chandra X-ray observations of SWIFT J0045.2+4151 (aka Sw J0045 aka GRB 150301C aka p[PFH2005] 622) DATE: 15/03/07 22:09:02 GMT FROM: David Burrows at PSU/Swift Kari A. Frank (PSU), David N. Burrows (PSU), Alessandro Maselli (INAF-IASFPA), Phil Evans (U. Leicester), Chryssa Kouveliotou (GWU), Ersin Gogus (Sabanci Univ.), Daniele Malesani (DARK/NBI): On Friday, March 6, 2014, beginning at 2015-03-06T16:29:31 (T0+468.4 ks relative to the Swift BAT trigger) we obtained a Chandra DDT observation at the position of the XMM-Newton source [PFH2005] 622 (Pietsch et al. 2005, ApJ 434, 483, ATel #7181), coincident with the BAT source SWIFT J0045.2+4151 (GCN #17512, GCN #17516, ATel #7166, ATel #7176). Net exposure time was 9.94 ks. The source was detected at the > 10 sigma level, with a count rate of 0.0023 (-0.0011,+0.0012) counts/s in the 0.5-8 keV band (errors are 90% confidence). The Chandra source position is: RA(J2000) = 00h 45m 14.78s Dec(J2000) = +41d 50m 34.53s with a 90% uncertainty of 0.8 arcsec. A total of 23 source counts were detected. This position is consistent with the XMM position of [PFH2005] 622 and the XRT position (ATel #7166). Assuming a powerlaw spectrum with photon index of 2, we find a flux 2.05e-14 (-0.97,+1.07) erg/cm^2/s (errors are 90% confidence). This is about 10 times fainter than the flux measured in the first XRT observation (ATel #7166), and similar to the archival XMM fluxes for [PFH2005] 622 reported in ATel #7181, though it is brighter than the 6.9e-15 erg/cm2/s reported by Pietsch et al. (2005). At the distance of M31, the observed flux corresponds to a luminosity of 9.5e35 erg/s.