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.
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"19550 results found.
- GRB 200306C: Swift detection of a burst with an optical counterpart
- LIGO/Virgo S200302c : No significant candidates in FRAM - TAROT - GRANDMA observations.
- LIGO/Virgo S200225q: No notable candidates in GOTO imaging
- GRB 200303A: Swift-BAT refined analysis
- GRB 200303A: Swift/UVOT Upper Limits
- GRB 200303A: GOTO observations upper limit
- GRB 200303A: Optical limit from CAHA
- GRB 200303A: Enhanced Swift-XRT position
- GRB 200303A: Swift detection of a burst
- LIGO/Virgo S200302c: No significant counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200302c: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S200302c: No counterpart candidates in HAWC observations
- LIGO/Virgo S200302c: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- LIGO/Virgo S200302c : no neutrino counterpart candidate in ANTARES search
- GRB 200228B: Mondy, TSHAO, AbAO and CrAO optical observations, afterglow candidate
- LIGO/Virgo S200225q : No significant candidates in TAROT - FRAM - GRANDMA observations.
- GRB 200228B: RATIR Optical Observations
- GRB 200228B: Liverpool Telescope imaging
- GRB 200228B: Swift/UVOT Upper Limits
- GRB 200228B: RATIR Optical Observations
- GRB 200227A: RATIR Optical Observations
- GRB 200227A: Mondy optical upper limit
- GRB 200228B: Enhanced Swift-XRT position
- Fermi-LAT Gamma-ray Observations of IceCube-200227A
- GRB 200228B: Swift detection of a burst
- GRB 200227A: Swift-XRT refined Analysis
- GRB 200227A: Swift-BAT refined analysis
- GRB 200227A: Swift/UVOT Upper Limits
- GRB 200227A: Enhanced Swift-XRT position
- HAWC-200216A: No Neutrino Counterpart in ANTARES Search
- GRB 200224A: Mondy optical upper limit
- LIGO/Virgo S200224ca : No significant candidates in TAROT - FRAM - GRANDMA observations
- IceCube-200227A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- GRB 200227A: Swift detection of a burst
- LIGO/Virgo S200224car: GRAWITA VST-ESO PARANAL observations.
- Konus-Wind observation of GRB 200219A
- GRB 200224A: Calar Alto 2.2m optical afterglow detection
- GRB 200219A: Chandra rapid ToO upper limit
- LIGO/Virgo S200225q: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S200224ca: no counterpart candidates in the Swift/BAT observations
- GRB 200224B: DDOTI/OAN optical observations report
- LIGO/Virgo S200224ca: No Counterparts in DDOTI/OAN Optical Observations
- LIGO/Virgo S200224ca: GRAWITA-Campo Imperatore observations.
- LIGO/Virgo S200225q: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200224ca: Subaru/Hyper Suprime-Cam follow-up observations
- LIGO/Virgo S200225q: No counterpart candidates in HAWC observations
- LIGO/Virgo S200225q : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S200224ca: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200225q: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- LIGO/Virgo S200225q: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S200224ca: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 200224A: RATIR Optical Observations and Confirmation of the Afterglow
- GRB 200224A: Swift/UVOT Detection
- GRB 200224A: Swift-XRT refined Analysis
- GRB 200224C: Fermi GBM Final Real-time Localization
- GRB 200224A: Tautenburg observations
- GRB 200224A: BOOTES-1 and 1.5m OSN optical observations
- Fermi trigger No 604213554: Global MASTER-Net observations report
- GRB 200224B: Fermi GBM Final Real-time Localization
- GRB 200224A: Swift detection of a burst
- Swift GRB200224.14: Global MASTER-Net observations report
- LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC-F30 observations
- LIGO/Virgo S200219ac: no counterpart candidate in SVOM/GWAC observations
- LIGO/Virgo S200219ac : No significant candidates in TAROT - FRAM - GRANDMA observations.
- GRB 200219C: OAJ afterglow confirmation
- GRB 200219A: UVOT Upper Limits
- GRB 200219C: Mondy and TSHAO optical observations
- GRB 200219C: Nanshan/NEXT optical upper limit and possible host galaxy from PanSTARRS
- GRB 200219C: Swift-XRT afterglow detection
- GRB 200219C: DDOTI Observations
- GRB 200219C: Tiled Swift observations
- LIGO/Virgo S200219ac: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S200219ac: No counterpart candidates in Fermi-LAT observations
- GRB 200219A: Swift-XRT refined Analysis correction
- GRB 200219A: Swift-XRT refined Analysis
- GRB 200219A: Enhanced Swift-XRT position
- LIGO/Virgo S200219ac: upper limits from AGILE/MCAL observations
- LIGO/Virgo S200219ac : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S200219ac: No counterpart candidates in HAWC observations
- LIGO/Virgo S200219ac: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- GRB 200216B: second epoch optical upper limit at Mondy observatory
- GRB 200219A: Swift detection of a short burst
- GRB 200216B: Mondy and AbAO optical upper limits
- LIGO/Virgo (S200213t/IceCube neutrino candidate: No counterpart candidates in the Swift-XRT Observations
- GRB 200216B: Swift-XRT refined Analysis
- LIGO/Virgo S200213t : No significant candidates in FRAM - OAJ - TAROT - GRANDMA observations
- GRB 200216B: z-band limit from NOT
- GRB 200216B: Swift/UVOT Upper Limits
- GRB 200216B: Enhanced Swift-XRT position
- GRB 200215A: RATIR Optical Observations
- GRB 200216B: Nanshan/NEXT early optical upper limit and possible host galaxy
- GRB 200216B: GMG upper limit
- GRB 200216B: Swift detection of a burst
- GRB 200215A: UKIRT H-band observations
- GRB 200215A: Swift/UVOT Upper Limits
- GRB 200215A: Enhanced Swift-XRT position
- GRB 200215A: Optical observations form Calar Alto 2.2m
- GRB 200215A: Liverpool Telescope upper limits
- LIGO/Virgo S200213t: Pre-discovery detections of MASTER OT J044008.76-651302.3
- GRB 200215A Possible host galaxy in PanSTARRS