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"7296 results found.
- Swift triggers (#524542) on a Galactic source
- GRB 120612A: Swift detection of a burst
- GRB 120521C redshift estimate
- GRB 120521C: Keck Observations
- GRB 120521C: Swift detection of a burst
- 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
- GRB 120419A: Swift-XRT and UVOT observations
- Swift Trigger 519874 is probably a noise event
- GRB 120404A, Optical Observations
- GRB 120401A: GROND Detection of an optical/NIR afterglow candidate
- GRB 120404A: Faulkes Telescope North afterglow confirmation
- GRB 120404A: Swift detection of a burst with an optical counterpart
- GRB 120403B: Swift detection of a burst
- GRB 120402A: Swift detection of a possible burst or noise
- GRB 120401A: Swift detection of a burst
- GRB 120328A: Swift detection of a burst
- GRB 120327A afterglow detection
- GRB 120327A: TAROT La Silla observatory optical detection
- GRB 120327A: Swift detection of a burst with an optical counterpart
- GRB 120326A: TAROT Calern observatory afterglow optical detection
- GRB 120326A: Swift detection of a burst
- GRB 120324A: CQUEAN rizY Observation
- GRB 120324A: Liverpool Telescope optical candidate
- GRB 120324A: UVOT Finding Chart Observation
- GRB 120320A: Swift/UVOT Upper Limits
- GRB 120320A: Swift detection of a burst
- GRB 120302A: Swift XRT refined analysis
- GRB 120312A: CrAO optical upper limit
- GRB 120311A: Optical follow-up
- GRB 120311A: C88 optical limits
- GRB 120312A: Swift/UVOT Upper Limits
- GRB 120312A: WHT candidate afterglow
- GRB 120312A: Swift detection of a burst
- GROND observations of GRB 120311A
- GRB 120311A: Liverpool Telescope optical candidate
- GRB 120308A : LOAO optical observation
- GRB 120302A: RTT150 optical observations
- GRB 120308A: Liverpool Telescope optical afterglow candidate
- GRB 120308A: Swift detection of a burst
- GRB 120302A: Swift-BAT refined position and a possible XRT and UVOT counterpart
- GRB 120305A: Swift detection of a short burst
- GRB 120302A: GROND detection of an afterglow candidate
- GRB 120227A: RAPTOR Limit During the Gamma-Ray Emitting Interval
- GRB 120224A: VLT/X-shooter observations
- GRB 120224A: optical observation in Mondy observatory
- GRB 120224A: GROND detection of the afterglow candidate
- GRB 120224A: Swift detection of a burst
- GRB 120219A: MASTER prompt and early optical limit and OT discussion
- GRB 120219A: 1.23m CAHA optical observations
- GRB 120219A: Swift detection of a burst
- GRB 120215A: Swift detection of a burst
- GRB 120211A : LOAO optical observations
- GRB 120213A: Swift detection of a burst
- GRB 120212A: Faulkes Telescope South afterglow candidate
- GRB 120211A: Swift detection of a burst
- Swift detection of a burst from LS I +61 303
- GRB 120202A: WHT, Gemini & UKIRT candidate afterglow
- GRB 120119A : LOAO Optical Observations
- GRB 120121A: Swift detection of a burst
- GRB 120119A: Swift detection of a burst with an optical counterpart
- GRB 120118B: Swift detection of a burst
- XRF 120118A: Optical candidate
- GRB 120116A: Gemini optical/IR candidate
- GRB 120116A: Optical observations at Crni Vrh
- GRB 120116A: Swift detection of a burst
- Swift detection of an SGR burst from AXP 4U 0142+61
- GRB 120106A: TAROT Calern observatory optical observations
- GRB 120106A: Swift detection of a burst
- GRB 120102A: Swift detection of a burst with an optical counterpart
- GRB 111228A, optical observations
- GRB 111229A: GROND afterglow candidate
- GRB 111229A: Swift detection of a burst
- GRB 111228A, optical observations
- GRB 111228A: TAROT Calern observatory. OT seems still bright
- GRB 111228A: Swift detection of a burst with an optical counterpart
- GRB 111225A: Swift detection of a burst with an optical counterpart
- Trigger 510075 is not a GRB
- GRB 111211A: optical ovservations at Mt. Terskol observatory
- Possible detection of pre-trigger X-ray emission from GRB 111215A by MAXI/GSC
- GRB 111215A: Swift detection of a burst
- GRB 111211A: NOT afterglow confirmation
- GRB 111211A: Swift/XRT target of opportunity observation
- GRB 111211A: GROND afterglow candidate
- GRB 111210A: GROND observations
- GRB 111210A: SDSS prior imaging
- GRB 111210A: Gemini-North candidate counterpart
- GRB 111210A: Swift detection of a burst
- GRB 111209A: TAROT La Silla observatory optical detection
- GRB 111209A: Swift detection of a long burst with an optical counterpart
- GRB 111204A: Swift detection of a burst
- GRB 111129A: Swift detection of a burst with an optical counterpart