GCN Circulars
GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search
To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.
Advanced Search Examples (click to copy):
subject:"Swift"body:"GRB"submitter:"Judith Racusin"43604 results found.
- GRB 040403, deep optical observations
- INTEGRAL-SPI/ACS GRB data: timing correction
- IBAS GRB alerts 1739, 1740, 1741
- HETE/IPN localization of GRB040403A (=H3143, a long burst) and GRB040403B(=H3144, a short/hard burst)
- GRB 040403: Optical observations
- GRB 040403: a long GRB detected with INTEGRAL
- Summary of recent bursts from SGR 1806-20 detected by INTEGRAL
- GRB 040329: hard burst detected by Konus-Wind and Helicon - Coronas-F
- IBAS GRB Alert 1694
- GRB040323: NIR Observations and Variable Object
- GRB 040319 (=H3128): An X-Ray-Rich GRB Localized by the HETE-2 WXM and SXC
- GRB 040323, a dark GRB ?
- short hard GRB 040322
- GRB 040323: a long GRB detected with INTEGRAL
- IBAS GRB alerts 1679, 1680, 1681
- GRB040223: Deep NIR NTT data re-analysis
- GRB 040223: XMM-Newton results
- GRB040223, improved XMM position
- IBAS Alert 1678: not a GRB
- GRB 031203: spectoscopic evidence for a 1998bw-like SN
- GRB 031203, possible supernova
- MASTER: RXTE GRB040308 optical observation
- IBAS results on a burst from SGR1806-20
- INTEGRAL detection of activity from SGR1806-20
- GRB 040228 Optical observations
- IPN triangulation of GRB040228 (H3066, H3067)
- GRB 040228 (=H3066?,=H3067?): A Long GRB Localized by the HETE-2 WXM
- GRB 040223: Deep NIR NTT observations
- GRB 040223 : Optical observation (non-detection)
- XMM-Newton Images of GRB 040223
- GRB 040223, VLA observations
- GRB 040223: REM IJK Observations
- GRB 040223 XMM-Newton observation ...
- GRB 031203 XMM-Newton observation
- GRB 040223: further offline analysis
- GRB 040223: a long GRB detected with INTEGRAL
- GRB031111, optical observations
- GRB031220: 2nd Chandra observation and X-ray afterglow candidate
- GRB031203: Chandra Observations
- GRB040106, follow-up radio observations
- GRB040106: refined X-ray transient position
- IBAS GRB alert 1379
- SN 2003dh/GRB030329 late-time optical spectroscopy
- GRB040106, Radio Observations
- GRB040106, likely optical afterglow
- GRB040106: Second Epoch Optical Observations
- GRB 031220: Optical observations of Chandra X-ray sources
- XMM-Newton Images of GRB 040106
- GRB040106: optical observations with REM+ROSS
- GRB031220: observation at Univercity of Miyazaki
- GRB 040106: Optical observations
- XMM-Newton observation of GRB040106
- GRB 040106 : Planned XMM-Newton observation
- GRB 040106 : peak flux
- GRB 040106 : a long GRB detected with INTEGRAL
- IPN triangulation of an intermediate burst from SGR1806-20
- GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
- GRB031220(=H2976): Observation with the Chandra X-ray Observatory
- GRB031225a triangulation (annulus)
- IPN triangulation of GRB031219 (large error box)
- GRB031220: Palomar Observations
- GRB 031220 : Kyoto Optical Observation
- GRB 031220: Optical observation at Tokyo Tech
- GRB 031203 I-band monitoring
- IPN triangulation of GRB031214 (short/hard; very intense; small error box)
- GRB 2974 follow-up observations
- GRB031203, improved XMM position
- GRB 031203: Discovery of a dust echo
- GRB031214 triangulation (annulus), [repost of GCN2487, subject corrected]
- GRB030921 triangulation (annulus)
- GRB 021203: A Normal GRB viewed far off axis?
- XMM-Newton Observations of GRB031203: Preliminary Images
- GRB 031203: Variable Radio Source
- GRB 031203: Magellan spectrum of possible GRB host
- GRB 031203: Optical/IR Astrometry
- IPN/HETE localization of GRB031203B (=H2949; large error box)
- GRB031203: ROSAT upper limits suggest XMM-S1 source as the transient
- XMM-Newton Observation of GRB031203
- GRB 031203: Deep NIR NTT & VLT observations
- GRB031203: K' Photometry of the likely GRB host
- XMM-Newton Observation of GRB031203
- GRB 031203: Radio detection
- GRB 031203: Further reports on December 4 observations
- GRB 031203: IR NTTobservations do not confirm REM detection
- GRB031203 : Optical Observation of Lulin Observatory
- GRB 031203: z ~ 10 or Fragmented Dust in the Circumburst Environment?
- GRB 031203: Apparent Spectral Break
- GRB 031203: IR REM Observations
- GRB031203: Optical Observations
- GRB031203: Planned XMM-Newton observation
- IPN triangulation of GRB031127A and B (quasi-simultaneous; large error boxes)
- GRB 031203: further analysis of INTEGRAL data
- GRB 031203: A long GRB detected with INTEGRAL
- IPN triangulation of GRB031201 (large error box)
- IPN triangulation of GRB031130 (large error box)
- GRB 030329: Planned XMM-Newton Observation
- IPN triangulation of GRB031120 (two large error boxes)
- GRB 031111B (= H2925) : Kyoto Optical Observation
- IPN/HETE localization of GRB031109 (=H2917; large error box)
- IPN detection of activity from SGR1806-20