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"19570 results found.
- GRB 151027A: the missing GeV component
- GRB 151031A: GROND observation
- GRB 151027B: ATCA radio detection
- GRB 151031A
- GRB 151031A: Swift/UVOT Detection
- GRB 151027B: RATIR Late-Time Upper Limits
- GRB 151031A: Enhanced Swift-XRT position
- GRB 151031A: VLT/X-shooter optical counterpart and redshift
- GRB 151031A: Swift detection of a burst
- GRB 151029A: MITSuME Ishigakijima upper limits
- GRB 151027A: Optical counterpart detection
- GRB 151029A: Swift/UVOT Detection
- GRB 151029A: Enhanced Swift-XRT position
- GRB 151029A: GROND afterglow observations
- GRB 151027A: SAO RAS optical observations
- GRB 151027A: NOT optical and NIR observations
- GRB 151027A: T100 observations
- GRB 151027B: Swift/UVOT Upper Limits
- GRB 151027A: continued GMG observation
- GRB 151027B: RATIR Observations
- GRB 151027B: Swift-XRT refined Analysis
- GRB 151027B: GROND Optical/NIR Afterglow Detection
- GRB 151027B: Enhanced Swift-XRT position
- GRB 151027A: UVOT Observations
- GRB 151027B: NOT optical afterglow candidate
- GRB 151027B: Swift detection of its 1000-th burst
- LIGO/Virgo O1 extended until January 12
- GRB 151027A: Early RAPTOR Observations
- GRB 151027A: GMG observation
- GRB 151027A: MITSuME Akeno Optical observation
- GRB 151027A: Weihai optical observations
- GRB 151027A: Enhanced Swift-XRT position
- GRB 151027A : ISON-NM early optical detection
- GRB 151027A: Swift detection of a burst with a bright optical afterglow
- LIGO/Virgo G194575: ASKAP followup
- LIGO/Virgo G184098: VLA follow-up of iPTF15cyk
- GRB 151021A: Skynet PROMPT-CTIO/DSO17 observations of the optical afterglow
- LIGO/Virgo G194575: Near-infrared follow-up with OAO-WFC
- LIGO/Virgo G194575: Kanata/J-GEM optical follow-up
- GRB 151022A: OSN optical upper limit
- GRB 151023A: RATIR Observations
- GRB 151023A: Swift/UVOT Upper Limits
- GRB 151023A
- LIGO/Virgo G194575: CQUEAN/LOAO observations
- GRB 151023A: Enhanced Swift-XRT position
- LIGO/Virgo G194575: LOFAR follow-up
- GRB 151022A: Swift/UVOT Upper Limits
- LIGO/Virgo G194575: RATIR Observations of Nearby Galaxies in the 1sigma Error Region
- LIGO Virgo G194575: MWA Observations
- LIGO/Virgo G194575: INTEGRAL search of temporally coincident prompt hard X-ray emission
- LIGO/Virgo G194575: RATIR Observations of Nearby Galaxies in the 1sigma Error Region
- LIGO/Virgo G194575: more details on transients from Pan-STARRS in the RA=1hr localisation region
- GRB 151023A: Swift detection of a burst
- GRB 151022A: RATIR Upper Limits
- LIGO/Virgo G194575: Fermi GBM Observations
- GRB 151022A: MITSuME Okayama upper limits
- LIGO/Virgo G194575: Mini-MegaTORTORA observations
- GRB 151022A: Enhanced Swift-XRT position
- GRB 151022A: Mondy optical upper limit
- GRB 151022A: MITSuME Okayama Ks-band upper-limit
- GRB 151022A: Swift detection of a burst
- GRB 151021A: MITSuME Okayama Ks-band upper-limit
- GRB 151021A: Swift/UVOT Detection
- GRB 151021A: MITSuME Okayama upper limits
- GRB 151021A: Enhanced Swift-XRT position
- GRB 151021A: Optical counterpart and redshift from X-shooter
- GRB 151021A: Swift detection of a burst
- LIGO/Virgo G184098: LOFAR follow-up
- GRB 151004A: Swift-XRT follow-up observations
- Trigger 659734: Swift detection of SAX J1750.8-2900 or other source near Galactic center
- GRB 151006A: Mondy optical upper limit
- GRB 151006A: OSN optical upper limit
- GRB 151006A: MITSuME Okayama Ks-band upper-limit
- GRB 151006A: Fermi-LAT detection
- GRB 151006A: Swift/UVOT Upper Limits
- GRB 151006A: Enhanced Swift-XRT position
- GRB 151006A: MITSuME Okayama upper limits
- GRB 151006A: Swift detection of a burst
- Trigger 657564 / GRB 151004A: Swift BAT and XRT refined analysis
- LIGO/Virgo G184098: ongoing Pan-STARRS search for optical transients
- Trigger 657564 / GRB 151004A: Swift/UVOT Upper Limits
- Swift Trigger 657564: XRT prompt analysis
- LIGO/Virgo G184098: MASTER OTs detection and Scenario Machine prediction
- GRB 151001A: RATIR Observations
- GRB 151001B: Swift/UVOT Upper Limits
- GRB 151001B: Swift-XRT refined Analysis
- GRB 151001A: Swift/UVOT Detection
- GRB 151001A: NOT imaging
- GRB 151001B: Enhanced Swift-XRT position
- GRB 151001A: Enhanced Swift-XRT position
- GRB 151001B: Swift detection of a burst
- GRB 151001A: Swift detection of a burst with an optical counterpart
- LIGO/Virgo G184098: spectral classification of PS15cci
- GRB 150925A: Swift/UVOT Upper Limits
- GRB 150925A: Enhanced Swift-XRT position
- GRB 150925A: Swift detection of a burst
- LIGO/Virgo G184098: LOFAR follow-up
- LIGO/Virgo G184098: ASKAP followup
- LIGO/Virgo G184098: ongoing Pan-STARRS search for optical transients
- LIGO/Virgo G184098: optical transient search with Kiso Schmidt telescope and KWFC on behalf of J-GEM collaboration