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"2803 results found.
- GRB 050813: Possible Short Swift-BAT GRB
- GRB 050730, optical observation
- Possible GRB 050805B: Swift-BAT trigger 149131 may be a burst
- GRB 050803: RTT150 optical observations
- GRB050803: CrAO optical observations, possible OT candidate
- GRB 050801: ROTSE-III Early Afterglow Break
- GRB 050801: ROTSE-III Detection of Possible Counterpart
- GRB050730: Swift-BAT detection of a weak burst
- Swift-BAT trigger 147918 is not a real GRB
- GRB050726: Swift-BAT detection of a weak burst
- GRB 050724: J-band observations
- GRB 050724: GMOS Imaging and Spectroscopy
- GRB 050724: Optical limit
- GRB050724: Refined analysis of the Swift-BAT possible short burst
- GRB 050724: possible host galaxy in DSS
- Swift-BAT detection of a possible GRB
- GRB050713: possible I-band afterglow
- GRB050709: A Possible Short-Hard GRB Localized by HETE
- H11603: An X-ray flare from V4641 Sgr, or a possible XRF
- H3804: A Possible New XRB Detected by HETE
- GRB 050607: MDM Observation
- GRB050528: updated Liverpool Telescope limits
- GRB050528: BOOTES optical candidate (retraction)
- Possible GRB050528: no candidate from Liverpool Telescope
- Swift-BAT detection of possible GRB 050528
- GRB 050509b: refined XRT/Chandra afterglow position analysis
- GRB 050525A: ROTSE-III Detection of Possible Counterpart
- GRB 050509b: Further Analysis of Keck LRIS Images
- GRB 050509b: Possible Optical Counterpart
- Keck/DEIMOS Spectrum of Possible Host Galaxy for GRB050509b
- Swift Detection of GRB050509b: A short duration burst
- GRB050505: Infrared observations
- Renewal of SGR 1806-20 activity
- GRB 050502: ROTSE-III Detection of Possible Counterpart
- Swift/BAT possible detection of a weak burst GRB050430
- GRB 050421: early Swift XRT analysis results
- GRB050418: Null Optical Observations
- GRB 050408: refined XRT analysis, no jet break seen yet
- Swift-BAT Detection of GRB 050412: A Bright, Long Burst
- GRB 050408: Swift XRT measurement of possible jet break
- GRB 050406 BAT refined analysis
- Swift-BAT detection of GRB 050406
- GRB050401: Radio observation at 610 MHz with GMRT
- GRB 050315: Variability Analysis of Swift BAT Time History
- GRB 050319: Detection of Possible Optical Counterpart
- GRB050316: MASTER optical observations
- GRB 050315: Swift-BAT further refined analysis
- Non-detection of GRB050315 in ATCA Radio Observations
- GRB 050306: optical afterglow
- Swift-BAT trigger 107873: No Swift XRT counterpart
- Swift-BAT trigger 107873 (GRB050309): possible X-ray counterparts
- GRB 050306: REM optical-infrared observations
- GRB 050306: Possible X-ray Afterglow Position from the Swift
- GRB 050306: Swift-BAT detection of a long burst
- GRB050215b: Faulkes North and SDSS limits on UKIRT candidate
- GRB 050215b: Swift XRT Source Variability
- GRB 050126: A NIR afterglow candidate in the revised XRT error circle
- ATCA observations of SGR 1806-20
- The giant outburst from SGR 1806-20
- GRB041219; RXTE ASM Observations
- GRB 041218: optical observations
- Deep RAPTOR observations during GRB 041219
- GRB041219c: Third Burst in One Day from Swift-BAT
- GRB 041219: PAIRITEL IR Observations, < 3 minutes after trigger
- GRB 041217: LCO40 Optical Observations and Possible Candidates
- GRB 041211: Infrared Observations
- GRB 041006 R observations in Loiano
- GRB041006, optical observation in CrAO
- Search for SN light in XRF 040912 with MEGACAM
- GRB 040916: Afterglow Color at Early Times
- GRB041006 (=HETE3570): optical observations
- GRB 040924: detection of possible host galaxy by Subaru
- GRB 040924: RTT150 optical observations
- XRF040916: continuing decay of OT
- XRF 040912, identification of CXO sources
- GRB040912 (= H3557): Chandra Observations Scheduled
- GRB040903 - A XRF?
- GRB040827: analysis of the XMM-Newton observation
- ROTSE-III Rapid Response to possible GRB 040903 (INTEGRAL #1972)
- Possible GRB 040903 - further analysis
- Possible GRB 040903 detected with INTEGRAL
- GRB 040827: Possible detection of optical afterglow
- MASTER: GRB040827 possible OT
- GRB040825A: optical observations
- GRB040825B: optical observations
- GRB040825B: Correction to GCN 2657
- XRF040812: possible afterglow second Chandra observation
- XRF040812: possible afterglow
- GRB040624: optical monitoring at TNG
- XRF 040701 - optical observations of the decaying Chandra source
- GRB040706:observation at University of Miyazaki
- GRB 040511: NIR observations with REM
- GRB 040423 (=H3175): A Long GRB Localized by HETE
- GRB 031203, possible supernova
- IPN triangulation of GRB040228 (H3066, H3067)
- GRB 031220: Optical observations of Chandra X-ray sources
- GRB040106: optical observations with REM+ROSS
- IPN triangulation of GRB031219 (large error box)
- GRB 031203: Magellan spectrum of possible GRB host
- GRB 031203: IR NTTobservations do not confirm REM detection