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"8472 results found.
- Swift Trigger 536502 is likely a noise fluctuation in coincidence with SAX J1818.6-1703
- GRB 121017A: Swift detection of a burst
- GRB 121011A: WSRT radio observation
- GRB 121011A: optical observations
- GRB 121011A: misprint in GCNC 13854
- GRB 121011A: MASTER-Net bell light curve
- Swift-BAT refined analysis of the SGR 1806-20 outburst (trigger 535747)
- GRB 121011A: Swift detection of a burst with optical afterglow
- Trigger 535747: Swift detection of an outburst from SGR1806-20
- Trigger 535733: Swift possible detection of SAX J1828.5-1037
- Swift Trigger 535026 is GRB 121001A: Swift-BAT refined analysis
- Swift Trigger 535026: Galactic Transient or possible GRB
- GRB 120927A: Swift detection of a burst
- GRB 120922A: Swift/UVOT Observations
- GRB 120923A: Gemini afterglow detection, high-z candidate
- GRB 120922A: TAROT La Silla observatory optical observations
- GRB 120923A: Swift detection of a burst
- GRB 120922A: GROND afterglow candidate
- GRB 120922A: Swift detection of a burst
- GRB 120919A: Swift-XRT observations
- Swift Trigger 534017 is probably not real.
- Swift Trigger 533836 is a new Galactic transient
- GRB 120913B: TAROT La Silla observatory optical detection
- GRB 120907A: ROTSE-III Optical Limits
- GRB 120907A: Swift detection of a burst with optical counterpart
- GRB 120821A: Swift/XRT observations
- GRB 120819A: GROND afterglow confirmation
- GRB 120819A: afterglow candidate from NOT
- GRB 120819A: Swift detection of a burst
- GRB 120816A: optical upper limit
- GRB 120816A: Swift detection of a burst
- GRB 120805A: Liverpool Telescope optical candidate detection
- GRB 120815A: GROND afterglow candidate
- GRB 120815A: TAROT La Silla observatory optical observations
- GRB 120811C: MASTER-Amur observations of fading OT
- GRB 120811C: Swift detection of a burst with an optical counterpart
- Trigger 530588: Swift detection of XMM J174457-2850.3
- GRB 120807A: Swift detection of a burst
- Fermi/GBM detection of an SGR-like burst
- Swift trigger 530214: uncertain if real or not
- GRB120805A: Liverpool Telescope observations
- GRB 120805A: Swift detection of a burst
- GRB 120804A: Swift detection of a short burst
- GRB 120803B: Swift-BAT refined analysis
- GRB 120803B: FTN possible afterglow candidate
- GRB 120803B: Swift detection of a burst
- GRB 120803A: Swift detection of a possible burst
- GRB 120802A: Swift detection of a burst
- GRB 120728A, Swift-BAT refined analysis
- GRB120729A - Faulkes Telescope North Optical Afterglow Candidate
- GRB 120729A: Swift detection of a burst with an optical afterglow
- GRB 120728A: Swift detection of a burst
- Swift Trigger 528925 is probably a noise fluctuation
- GRB 120724A: FTN optical afterglow candidate
- GRB 120724A: Swift detection of a burst
- GRB 120709A: Swift re-observation of the field of the X-ray counterpart candidate.
- GRB 120722A: VLT/X-shooter redshift of the host galaxy
- GRB 120722A: GROND detection of the afterglow
- GRB 120722A: Correction for GCN circ.13500
- GRB 120722A: Xinglong TNT optical afterglow candidate
- GRB 120722A: Swift detection of a burst
- VLT/FORS2 redshift of GRB120716A
- GRB 120716A: GROND confirmation of the optical/NIR afterglow
- GRB 120716A: Optical decay from NOT
- GRB 120716A: Candidate Optical Afterglow from PTF
- GRB 120714B: Swift/UVOT Detection
- GRB 120714B: GROND confirmation of fading afterglow
- GRB 120714B: Position Correction and Candidate Optical Afterglow
- GRB 120714A: Swift-BAT refined analysis
- GRB120714A: UVOT non-detection
- GRB 120712A: GROND Detection of the Optical/NIR Afterglow Candidate and photo-z
- GRB 120712A: Swift detection of a burst with optical afterglow
- GRB 120709A: Swift/UVOT Observations
- Swift detection of GRB 120711B or a new Galactic transient
- GRB 120703A: Swift detection of a bright burst with an optical afterglow
- GRB 120630A: Swift-BAT/-XRT/-UVOT refined analysis
- GRB120624B: Chandra observations and afterglow detection
- GRB 120624B: Further analysis of the HAWKI observations
- GRB 120624B: GROND upper limits
- GRB 120624B: NIR counterpart candidate from HAWKI
- Swift detection of Ginga 0834-430
- Swift detection of IGR J17062-6143
- GRB 120624B: optical observations
- GRB 120624A: Fermi GBM observation
- Swift Trigger 524949: Noise fluctuation near a galaxy
- Swift triggers (#524542) on a Galactic source
- GRB 120612A: Swift detection of a burst
- GRB 120521C redshift estimate
- GRB 120521C: Swift detection of a burst
- Swift starts a new program to find fainter transients
- GRB 120521B: Swift detection of a burst
- GRB 120521A: Swift detection of a short burst
- GRB 120514A: GROND upper limits
- GRB 120514A: Swift detection of a burst
- GRB 120510B/Fermi Trigger 358364818: MASTER possible OT candidate
- GRB 120422A: VLT/X-shooter spectroscopy of the GRB counterpart
- GRB 120422A GROND observations
- GRB 120422A: Gemini redshift of candidate host
- GRB 120422A: Gemini observations
- GRB 120422A: Swift detection of a burst