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"18476 results found.
- MASTER: HETE Alert 3274 optical observation
- GRB 040511, very fast decay?
- GRB 030324: Detection and Color of Host Galaxy
- GRB 040511: NIR observations with REM
- GRB040511: Candidate optical/NIR afterglow
- GRB 040511: ROTSE-III Rapid Optical Upper Limits
- GRB 040511: Second Epoch Optical Observations
- GRB 040511: Optical observations
- GRB 040511: Optical Observations
- GRB040511: Optical Observations
- GRB040511: Optical Observations
- GRB 040423 (=H3175): A Long GRB Localized by HETE
- GRB040422 : I-band follow-up observation at Lulin Observatory
- GRB 040422: ROTSE-IIIb Prompt Optical Limits
- GRB040422, BVRcIc field calibration
- GRB 040422,optical observation
- GRB 040422: a long GRB detected with INTEGRAL
- GRB 040403, deep optical observations
- MASTER: HETE Alert 3163, 3167 technical optical observation
- 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
- GRB040323: NIR Observations and Variable Object
- GRB 040323, a dark GRB ?
- GRB040223, improved XMM position
- GRB 031203, possible supernova
- MASTER: RXTE GRB040308 optical observation
- IBAS results on a burst from SGR1806-20
- RXTE GRB040229 optical observation: no candidate
- GRB040228 : KISO optical follow-up observation
- 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
- GRB031111, optical observations
- GRB031220: 2nd Chandra observation and X-ray afterglow candidate
- GRB040106: refined X-ray transient position
- GRB040106, likely optical afterglow
- GRB 031220: Optical observations of Chandra X-ray sources
- XMM-Newton Images of GRB 040106
- GRB031220: observation at Univercity of Miyazaki
- XMM-Newton observation of GRB040106
- GRB 040106 : peak flux
- GRB031220(=H2976): TNG R-band Observation of the Chandra X-ray Sources
- GRB031220(=H2976): Observation with the Chandra X-ray Observatory
- GRB 031220 : Kyoto Optical Observation
- GRB 031220: Subaru observation
- GRB 031220: Optical observation at Tokyo Tech
- GRB 2974 follow-up observations
- GRB031203, improved XMM position
- XMM-Newton Observations of GRB031203: Preliminary Images
- GRB031203: ROSAT upper limits suggest XMM-S1 source as the transient
- XMM-Newton Observation of GRB031203
- GRB031203: K' Photometry of the likely GRB host
- XMM-Newton Observation of GRB031203
- GRB 031203: IR NTTobservations do not confirm REM detection
- GRB 031203: Apparent Spectral Break
- GRB031203: Planned XMM-Newton observation II
- GRB 031203: IR REM Observations
- GRB031203: Optical Observations
- GRB 031203 XMM-Newton observation
- GRB031203: Planned XMM-Newton observation
- GRB 030329: Planned XMM-Newton Observation
- GRB 031111B (= H2925) : Kyoto Optical Observation
- IPN triangulation of GRB031107 (two large error boxes)
- GRB 031111, optical observations
- GRB031026: 1.2mm upper limit with MAMBO at the IRAM 30m
- IPN triangulation of GRB031027 (small error box)
- Lulin optical follow-up observations of GRB031026
- GRB 031026 (=H2882): Evidence for High Redshift from Prompt
- GRB030329: radio observations at RT-22 (CrAO)
- IPN triangulation of GRB031016 (two large error boxes)
- Ongoing Bursting Activity from SGR 1806-20 detected with IBAS
- XRF 030824: additional observations at CFHT
- SGR 1806-20 bursts with INTEGRAL and IBAS announcement on Soft Gamma-Ray Repeaters
- XRF 030723: Subaru Optical Observations
- A burst from SGR 1806-20 detected with IBAS
- XRF 030824: Early follow-up observation at Kiso observatory
- XRF 030723: Detection of the likely host galaxy
- XRF030824 (=H2821): An X-Ray Flash Localized by the HETE WXM
- XRF030823 (=H2818): An X-Ray Flash Localized by the HETE WXM and SXC
- GRB030913: Subaru Optical Observations
- GRB 030913, optical candidate
- GRB 030913, BOOTES observations
- IPN triangulation of GRB030916 (possible short/hard GRB; large error box)
- GRB030913: wide field imaging (7 sq.deg) of the error box by MASTER
- GRB030913 (=H2849): A GRB Possibly Localized by HETE
- XRF 020427: Gemini-South Spectroscopic Observations of the Host
- XRF030824: Optical observations
- IBAS detection of bursts from SGR 1806-20
- GRB030823: optical observation at Tokyo Tech
- Lulin follow-up observations of GRB030823
- GRB 030817 = H2808 TAROT optical observations
- SGR 1808-20 (=H2802): A Possible new SGR
- XRF030723(=H2777): Chandra Fading X-ray Afterglow Confirmed
- XRF030723, BVRcIc field photometry update