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.
- VLA observations of short burst GRB 090417A
- GRB 090417B: optical observations
- GRB 090412: Fermi GBM detection
- Swift-BAT trigger 348781: almost certainly not a burst
- Fermi GBM Detection of a weak source
- GRB 090404: Swift detection of a burst
- GRB 090401B: Swift detection of a burst
- GRB 090328B: MASTER-Irkutsk prompt optical short burst observations
- GRB 090401: Swift detection of a burst
- GRB090323: Optical observations from NOT
- GRB 090328: Possible Swift/XRT detection
- GRB 090323: TLS detection at 5 days, no break
- GRB 090320B: MASTER-Net prompt optical observations
- GRB 090323 TLS detection - still bright
- GRB 090323: Possible XRT Counterpart
- GRB 090313: VLT spectroscopy
- GRB090305B: MASTER-net prompt optical short burst observations
- GRB 090306B: Possible XRT afterglow
- GRB 090306: Swift detection of a possible burst
- GRB 090303: Fermi GBM detection
- GRB 081211B: Nearby cluster
- GRB 090201: Swift-XRT detection of the possible X-ray afterglow
- AXP 1E1547.0-5408: Fermi GBM observations
- Trigger 340734: Swift detection of a possible short burst
- GRB 090118 (BATSS): GRT Optical Observation
- GRB 090118: GROND Upper Limits
- GRB 090118: Possible burst detection from Swift-BAT slew data
- GRB090117: Swift-XRT detection of a possible candidate afterglow
- GRB090113: XRT position
- GRB 090112: Fermi GBM detection
- GRB 090107B: Swift-XRT detection of possible afterglow
- GRB 090107: Swift detection of a burst
- GRB 081228, Swift-BAT refined analysis
- GRB 081228: Swift-XRT Team refined analysis
- GRB 081226: Swift-XRT refined analysis
- GRB 081226A: Swift UVOT Upper Limits
- GRB 081226: Gemini-South spectrum of possible afterglow
- GRB 081226: Swift detection of a possible short-hard burst
- GRB 081211B: Further Swift-XRT analysis
- Possible GRB 081211B: Swift/UVOT Upper Limits
- Possible GRB 081211B - Swift-XRT analysis
- GRB 081211B(?): Possible burst detection from Swift-BAT slew data
- GRB 081211: Swift-BAT refined analysis
- GRB 081210: Swift-BAT refined analysis
- GRB 081128: optical observation in CrAO
- GRB 081204: Swift XRT afterglow candidate
- GRB 081203B: Swift-XRT candidate afterglow.
- GRB 081130B: MASTER prompt optical observations
- GRB 081128: optical observation
- GRB 081130B: Fermi GBM detection
- GRB 081128A: optical observations
- Trigger 335971: Swift possible detection of a burst
- GRB081128 : Lulin optical follow-ups
- GRB 081128: Swift detection of a burst
- GRB 081126: Confirmation of the Optical Afterglow
- Fermi GBM detection of a weak source
- GRB 081118: optical afterglow candidate
- GRB 081109A: confirmation of possible detection host galaxy
- GRB 081024B: Swift-XRT late-time observations
- Swift-BAT refined analysis of trigger 334129
- GRB 081109A: Possible Swift-UVOT detection
- GRB 081109A: Faulkes Telescope South observations
- GRB 081109A: Swift-XRT refined analysis
- Swift-BAT Trigger 334129: possible burst
- GRB 081101 (or SGR 0623-0006 ): Fermi GBM detection
- GRB 081024B: new Swift-XRT observations
- Fermi LAT/GBM short-hard GRB 081024B: Possible TLS Afterglow (Corrected)
- Fermi LAT/GBM short-hard GRB 081024B: Possible TLS Afterglow
- GRB 081025: TLS upper limits
- GRB 081024B: Swift-XRT further observations
- GRB 081025: Swift-XRT position
- GRB 081024B: Swift-XRT observations
- GRB 081024: Swift-XRT refined analysis
- Swift detection of a possible burst (trigger 332287)
- GRB 081011: Swift XRT refined analysis
- GRB 081016: Swift-XRT candidate afterglow detection
- GRB 081007 and GRB 081007B: Fermi GBM detection
- GRB 081003A: Swift-XRT Team position and analysis
- Swift discovery of a new Soft Gamma Repeater SGR 1550-5418
- GRB080928: Gemini-South Absorption Redshift
- Swift detection of a possible GRB (trigger 325707)
- GRB 080916C: Swift/XRT detection of possible afterglow
- GRB 080916B: Swift UVOT Refined Analysis
- GRB 080905B: Refined UVOT Analysis
- GRB 080906: Swift detection of a burst with optical afterglow
- GRB 080905B: Swift detection of a burst with possible optical counterpart
- SGR 0501+4516: preliminary results of the first XMM-Newton observation
- SGR 0501+4516: Detection of possible optical counterpart
- SGR 0501+4516: WHT observations of the possible near-infrared counterpart
- GRB 080828: Swift-XRT detection of a possible X-ray afterglow
- Swift trigger 322590: BAT detection of a possible burst
- Enhanced Swift-XRT position of SGR 0501+4516
- SGR 0501+4516: GMRT Radio Observation at 618 MHz
- SGR 0501+4516: Swift XRT measure of the spin period
- SGR 0501+4516: Astrotel-Caucasus optical observations
- SGR 0501+4516: UKIRT detection of possible infra-red counterpart
- GRB 080822 (SGR 0501+4516): archival optical observations
- GRB 080810: KANATA optical-NIR observation, update
- GRB080804: Gemini South redshift confirmation
- GRB 080805: GROND detection of possible afterglow