q Gamma-ray Burst 110213B

Gamma-ray Burst 110213B

(All information courtesy of the instrument teams.)

Previous IAU Circulars

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Results of Observations

GCN NOTICE
H. Negoro, M. Nakajima, H. Ozawa, F. Suwa (Nihon U.), N. Kawai, M. Morii, K. Sugimori, R. Usui, T. Toizumi (Tokyo Tech), M. Serino, T. Mihara, Y.E. Nakagawa, M. Sugizaki, T. Yamamoto, T. Sootome, M. Matsuoka (RIKEN), K. Kawasaki, S. Ueno, H. Tomida, M. Kohama, M. Ishikawa (JAXA), A. Yoshida, K. Yamaoka, S. Nakahira (AGU), H. Tsunemi, M. Kimura (Osaka U.), Y. Ueda, N. Isobe, S. Eguchi, K. Hiroi (Kyoto U.), A. Daikyuji (Miyazaki U.), A. Uzawa, T. Matsumura, K. Yamazaki (Chuo U.) report on behalf of the MAXI team:
MAXI/GSC triggered at UT 2011-02-13T14:31:48 on a bright uncatalogued X-ray transient source. Judging from its location and spectral hardness ratio, this transient is probably a gamma-ray burst. Since the emission was detected only for a fraction of the triangular transit response, the uncertainty of its position along the scan direction is large. The center of the error box is
(R.A., Dec) = (+41.768, 0.952 deg) = (02 47 04, 00 57 07)(J2000)
with an uncertainty of 0.5 deg (90% containment radius). The preliminary flux of the transient source was 1.3 Crab (2-4 keV), 2.2 Crab (4-10 keV), and 3.5 Crab (10-20 keV). There was no significant detection at the transit location in the previous orbit (92 min before the detection) with an upper limit of 20 mCrab. There is no known bright X-ray source at the detected position.
Follow-up observations are encouraged.
GCN NOTICE
M. Morii, N. Kawai, K. Sugimori, R. Usui, T. Toizumi (Tokyo Tech), H. Negoro, M. Nakajima, H. Ozawa, F. Suwa (Nihon U.), , M. Serino, T. Mihara, Y.E. Nakagawa, M. Sugizaki, T. Yamamoto, T. Sootome, M. Matsuoka (RIKEN), K. Kawasaki, S. Ueno, H. Tomida, M. Kohama, M. Ishikawa (JAXA), A. Yoshida, K. Yamaoka, S. Nakahira (AGU), H. Tsunemi, M. Kimura (Osaka U.), Y. Ueda, N. Isobe, S. Eguchi, K. Hiroi (Kyoto U.), A. Daikyuji (Miyazaki U.), A. Uzawa, T. Matsumura, K. Yamazaki (Chuo U.) report on behalf of the MAXI team:
We report further analysis of MAXI/GSC GRB 110213B (GCN #11716). The refined position of the GRB is
(R.A., Dec) = (+41.61 deg, +1.19 deg) = (02 46 27, +01 11 14)(J2000)
with a rectangular 90% statistical error box with the following corners:
```
(R.A., Dec) = (+41.62 deg, +1.11 deg) = (02 46 29, +01 06 23)(J2000)
(R.A., Dec) = (+41.53 deg, +1.18 deg) = (02 46  7, +01 10 48)(J2000)
(R.A., Dec) = (+41.61 deg, +1.27 deg) = (02 46 26, +01 16  2)(J2000)
(R.A., Dec) = (+41.70 deg, +1.19 deg) = (02 46 48, +01 11 37)(J2000)
```
Without assumptions on the source constancy, we obtain a rectangular error box with the following corners:
```
(R.A., Dec) = (+41.40 deg, +0.87 deg) = (02 45 36, +00 52 14)(J2000)
(R.A., Dec) = (+41.31 deg, +0.94 deg) = (02 45 13, +00 56 41)(J2000)
(R.A., Dec) = (+41.75 deg, +1.42 deg) = (02 46 59, +01 25 10)(J2000)
(R.A., Dec) = (+41.84 deg, +1.35 deg) = (02 47 22, +01 20 45)(J2000)
  
```
There is additional systematic uncertainty of 0.2 deg (90% containment radius).
GCN Circular #11722
S. Golenetskii, R.Aptekar, E. Mazets, V. Pal'shin, D. Frederiks, P. Oleynik, M. Ulanov, D. Svinkin, and T. Cline on behalf of the Konus-Wind team, report:
The GRB 110213B discovered and localized by MAXI/GSC (Negoro et al., GCN 11716) was detected by Konus-Wind in the waiting mode at T0(KW)=52293 s UT (14:31:33).
The burst light curve shows a single pulse with a duration of ~50 s.
As observed by Konus-Wind, the burst had a fluence of (1.77 +/- 0.16)x10^-5 erg/cm2 (in the 20 - 1400 keV range).
Modeling the K-W 3-channel time-integrated spectrum (from T0 to T0+50 s) by a power law with exponential cutoff model: dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep) yields alpha = -1.52 +/- 0.25, and Ep = 123 +/- 19 keV.
All the quoted errors are estimated at the 1 sigma confidence level.
The K-W light curve of this burst is available at http://www.ioffe.rssi.ru/LEA/GRBs/GRB110213B/
GCN Circular #11725
S. Nakahira (AGU), N. Kawai, M. Morii (Tokyo Tech), and H. Negoro (Nihon U.) report on behalf of the MAXI team:
Swift observed the field of GRB 110213B (Negoro et al., GCN Circ. 11716) centered at the refined MAXI/GSC position reported by Morii et al. (GCN Circ. 11720) for 2 ks from 2011-02-14T03:42:19 (T0+47 ks).
We find three point sources in the XRT field of view:
```
Source          (R.A., Dec.)  J2000                         flux
------   -----------------------------------------------   -------
  A      (41.562 deg, +1.245 deg)= (02 46 15, +01 14 42)   0.008 c/s
  B      (41.757 deg, +1.146 deg)= (02 47 02, +01 08 46)   0.029 c/s
  C      (41.550 deg, +1.391 deg)= (02 46 12, +01 23 28)   0.003 c/s
```
Source A is located 0.1' from 1RXS J024615.3+011427, a RASS source identified to an AF star. Source C is located 0.1' from a quasar Q 0243+011. No catalogued source was found for Source B.
Source B, the brightest of the three, and found near the edge of the field of view, is the most likely candidate for the afterglow of GRB 110213B. Another Swift observation is planned to confirm its fading.
We thank the Swift operation team for performing a prompt TOO observation and making the data available quickly.
GCN Circular #11732
S. B. Cenko (UC Berkeley), E. O. Ofek, S. R. Kulkarni (Caltech), and A. Rau (MPE Garching) report on behalf of a larger collaboration:
We have imaged the location of the possible X-ray afterglow (Source "B"; Nakahira et al., GCN 11725) of the MAXI GRB110213B (Negoro et al., GCN 11716) with the automated Palomar 60-inch telescope. Observations began at 3:38 UT on 2011 February 15 (~ 37.1 hours after the burst) in the r' filter.
We detect a source near the reported XRT position with coordinates (J2000.0):
02:47:01.41 +01:08:46.3
Using several nearby objects in the USNO-B1 catalog for reference, we measure a magnitude at this time of R = 19.8. No object is present at this location, either in the USNO-B1 catalog or the Digitized Sky Survey. Given the positional coincidence and the relative brightness, we consider it likely this is the optical afterglow of GRB110213B. However, future observations to establish fading will be required for confirmation.
GCN Circular #11735
S. B. Cenko, J. S. Bloom, and A. A. Miller (UC Berkeley) report on behalf of a larger collaboration:
The location of the X-ray (Nakahira et al., GCN 11725) and optical (Cenko et al., GCN 11732) afterglow of GRB 110213B (Negoro et al, GCN 11716) was observed repeatedly over the seven year period beginning in 1998 as part of the SDSS Stripe 82 Survey (Bramich et al., MNRAS 2008, 386, 887). We have extracted all images covering this location from the SDSS Stripe 82 database to create stacked frames in the g, r, and i filters. A false-color composite image of the afterglow location can be found at:
http://astro.berkeley.edu/~cenko/public/grb/GRB110213B/sdss.png
Using 10 nearby point sources from SDSS for astrometry, we measure a revised position for the P60 optical afterglow candidate of (J2000.0):
RA: 02:47:01.45 Dec: +01:08:46.5
The measured uncertainty in the P60-SDSS astrometric tie is 100 mas in each coordinate.
Offset by 0.9" from the location of the afterglow, we find an extended source in the pre-outburst SDSS Stripe 82 imaging in all three filters. We measure coordinates (J2000.0) for this source:
RA: 02:47:01.41 Dec: +01:08:47.2
Using several nearby point sources from SDSS for comparison, we measure magnitudes of g' = 23.7, r' = 22.8, i' = 22.3 Additional emission is marginally detected in the i' filter approximately 3" south of this position, but its relation to this object is unclear.
This extended source could be a relatively nearby host galaxy for GRB110213B, although the red colors are somewhat unusual for GRB hosts.
GCN Circular #11736
S. B. Cenko (UC Berkeley), J. X. Prochaska (UC Santa Cruz / Lick Observatory), A. Cucchiara, D. A. Perley, and J. S. Bloom (UC Berkeley) report on behalf of a larger collaboration:
We have obtained a spectrum of the candidate optical afterglow of GRB 110213B (Negoro et al., GCN 11716) with the Gemini Multi-Object Spectrograph mounted on the 8-m Gemini South telescope. Observations began at 00:44 UT on Feb. 16 and cover the wavelength range from 3900 - 6700 A.
Superposed on a smooth continuum, we detect a series of strong, narrow absorption lines corresponding to Mg I, Mg II, Fe II, and Fe II* at a common redshift of z = 1.083. The detection of fine structure lines firmly establishes this as the redshift of the GRB host galaxy.
An additional, strong Mg II absorption system is also present at z = 0.717. This may be related to the potential host candidate identified in pre-outburst SDSS Stripe 82 imaging (Cenko et al., GCN 11735).
At z = 1.083, the prompt fluence measured by Konus (Golenetskii et al., GCN 11722) correponds to a prompt isotropic energy release of 5.5e52 erg (20 - 1400 keV observer-frame bandpass).
We wish to thank the staff at Gemini Observatory, in particular Fredrik Rantakyro, for the prompt execution of these observations.
GCN Circular #11743
J. Elliott (MPE Garching), A. Nicuesa Guelbenzu (TLS Tautenburg), T. Kruehler and J. Greiner (both MPE Garching) report on behalf of the GROND team:
We observed the afterglow (Cenko et al., GCNs #11732, 11736) of GRB 110213B (Negoro et al., GCN #11716 & Morii et al., GCN #11720) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008, PASP 120, 405) mounted at the 2.2m MPI/ESO telescope at La Silla Observatory (Chile).
Observations started at 01:22 UT on 16.02.2011, 2.45 days after the GRB trigger and were performed at high airmass.
Based on a stacked image with exposure time of 460 s, we estimate a preliminary r' band magnitude of r' = 20.8 +/- 0.1 calibrated against SDSS field stars. This implies a fading with respect to the earlier measurement of Cenko et al. (#GCN 11732). In addition, the SED of the object is consistent with a power-law, and hence we confirm the source as the optical afterglow of GRB 110213B.
GCN Circular #11748
R. Margutti, (INAF-OAB), Nakahira (AGU), M. Morii, N. Kawai (Tokyo Tech), H. Negoro (Nihon U.) and A. Melandri (INAF-OAB) report on behalf of the Swift-XRT and MAXI team:
The Swift-XRT conducted a second observation of GRB 110213B (Negoro et al. GCN. Circ. 11716), gathering 4.9 ks of data between T0+250ks and T0+275 ks. Source B reported by Nakahira (GCN Circ. 11725) has faded to a level of 0.005 +/- 0.001 count/sec, with a power-law decay index of alpha= -1.4 +/- 0.3. This source is thus confirmed as the X-ray afterglow of GRB 110213B.
The results of the XRT-team automatic analysis are available at http://www.swift.ac.uk/xrt_products/00020157.
This circular is an official product of the Swift-XRT team.
GCN Circular #11749
S. R. Oates (MSSL-UCL) & R. Margutti, (INAF-OAB) reports on behalf of the Swift-UVOT team
The Swift/UVOT began settled observations of the field of the MAXI GRB 110213B ~13hrs after the trigger (Negoro et al., GCN Circ. 11716). The optical afterglow detected by P60 (Cenko et al, GCN Circ. 11732, 11735) and GROND (Elliott et al, GCN Circ. 11743) only lies in the UVOT field of view for 3 images, one per filter (white, v and u) obseved at ~3 days after the trigger.
Preliminary magnitudes using the UVOT photometric system (Poole et al. 2008, MNRAS, 383, 627) for the single exposures at the location of the optical afterglow are:
```
Filter  T_start(s)  T_stop(s)   Exp(s)       3sigUL
#####################################################
wh        256170     256432      259         > 20.78
v         256438     256691      249         > 19.23
u         255901     256164      259         > 19.62
#####################################################
```
The values quoted above are not corrected for the Galactic extinction due to the reddening of E(B-V) = 0.04 in the direction of the burst (Schlegel et al. 1998).

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Jochen Greiner, last update: 18-Feb-2011 [Disclaimer]