Gamma-ray Burst 970111

The BeppoSAX Gamma Ray Burst Monitor (GRBM) was triggered on Jan. 11. 9:44 UT. A Gamma Ray Burst was observed both with the GRBM and one of the WFC. A follow-up observation centered on the accurate position derived from WFC data has been performed less then 16 hours after the burst.

Previous IAU Circulars

• IAUC 6533 Discovery with WFC onboard BeppoSAX
  
• IAUC 6539 2 X-ray sources in BeppoSAX pointing; 3 faint sources in ROSAT All-Sky-Survey (1991)
• IAUC 6544 Optical photometry
• IAUC 6545 Radio source coincident with BeppoSAX source 'a'; Ulysses-BATSE triangulation ring
• IAUC 6559 Spectroscopic ID of two galaxies within 1" of the radio source
• IAUC 6567 ROSAT HRI observations detects BeppoSAX source 'A', but not 'B'
• IAUC 6569 Revised WFC location and reduced error circle of GRB
• IAUC 6571 Reduced IPN triangulation arc; radio source inside new error box detected at Westerbork
• IAUC 6574 BVI images of the refined error-box: no variable source brighter than V = 19.
• IAUC 6598 Calar Alto observations: no fading optical object down to B=23 and R=22.6 mag.

• The BeppoSAX pointing on Jan. 12/13 reveals two sources A and B (IAUC 6539) within the 10 arcmin GRB error box at positions
  1SAX J1528.8+1944
  1SAX J1528.8+1937.
  The relative brightnesses of these sources in the MECS and LECS images reveal their different spectral hardness.
• Three very faint sources are found in the ROSAT All-Sky-Survey data (taken Aug. 5-7, 1991). One of these sources coincides with the BeppoSAX source B, while the BeppoSAX source A appears to be resolved into two ROSAT sources.
• Positions and error radii of the various sources are overplotted on the digitized POSS image.
  The large circle centered on the image represents the 10 arcmin error radius of the GRB position detected with the BeppoSAX WFC (IAUC 6533). Circles A and B correspond to the 1 arcmin error radii of the two sources detected in the BeppoSAX MECS/LECS pointing on January 12/13, about 16 hours after the burst (IAUC 6539). The three small circles represent the 45 arcsec error radii of the faint X-ray sources present in the ROSAT All-Sky survey data (see IAUC 6539).
• A. Connors (UNH) communicated for the COMPTEL team: GRB 970111 occurred at 44 deg zenith angle of GRO, thus being in the COMPTEL FOV. In quick-look imaging of COMPTEL data, no signal is seen at all. In the COMPTEL telescope lightcurve there might be a slight peak at 1-2 s; and another at about 45 s after trigger; but these are no more significant than the peak about 20 s before the trigger.
• ROSAT HRI observation on January 16, 1997 for a total of 1305 sec. Three sources are detected, one of which is inside the reduced GRB location (IAUC 6545). This source RX J152845+1944.5 coincides with the BeppoSAX source 'A' (IAUC 6539), the radio source VLA J1528.7+1945 (IAUC 6545) and the two galaxies (IAUC 6559). See the scetch below for the relative locations of the various sources.
  The large circle is the 10 arcmin GRB error box, 'A' and 'B' denote the BeppoSAX sources detected during the pointings, the circles labeled 1-3 are the X-ray sources from the RASS (1991), and the squares denote the three sources found in the HRI pointing on Jan. 16, 1997.
• Radio image (from D. Frail) showing the revised error box (IAUC 6569). None of the X-ray or radio sources reported so far are within the new error box!
  
• 1507.04081 from 16 Jul 15
  S. Guiriec et al.: CGRO/BATSE Data Support the New Paradigm for GRB Prompt Emission and the New L$_i^nTh$-E$_peak^nTh$ L$_i^nTh$-E$_peak^rest$ L$_i^nTh$-E$_i^nTh$ L$_i^nTh$-E$_i^rest$ relation
  The paradigm for GRB prompt emission is changing. Since early in the CGRO era, the empirical Band function has been considered a good description of the keV-MeV spectra although its shape is very often inconsistent with the predictions of the pure synchrotron emission scenarios. We have recently established a new observational model analyzing data of the NASA Fermi Gamma-ray Space Telescope. In this model, GRB prompt emission is a combination of three main emission components: (i) a thermal-like component that we interpreted so far as the jet photosphere emission, (ii) a non-thermal component that we interpreted so far as synchrotron radiation, and (iii) an additional non-thermal (cutoff) power-law most likely of inverse Compton origin. In this article we reanalyze some of the bright GRBs observed with CGRO/BATSE with the new model, namely GRBs 941017, 970111 and 990123. We conclude that BATSE data are fully consistent with the recent results obtained with Fermi: some bright BATSE GRBs exhibit three separate components during the prompt phase with similar spectral parameters as these reported from Fermi data. In addition, the analysis of the BATSE GRBs with the new model results in a relation between the time-resolved energy flux of the non-thermal component and its corresponding $\nu$F$_\nu$ peak energy (i.e., F$_{i}^{nTh}$-E$_{peak,i}^{nTh}$) that has a similar index as the one initially derived from Fermi data. For GRBs with known redshift (z) this results in a possible universal relation between the luminosity of the non-thermal component and its corresponding $\nu$F$_\nu$ peak energy in the rest frame (i.e., L$_{i}^{nTh}$-E$_{peak,i}^{NT,rest}$). We estimated z for GRBs 941017 and 970111 using GRB 990123--with z=1.61--as a reference. The estimated z for GRB 941017 is typical for long GRBs and the estimated z for GRB 970111 is right in the range of the expected values for this burst.