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"19549 results found.
- GRB 200215A: Swift detection of a burst
- LIGO/Virgo S200213t: MASTER possible Kilonova candidate in PGC315337
- LIGO/Virgo S200213t: No neutrino candidates at Pierre Auger Observatory
- LIGO/Virgo S200213t: MASTER OT detection in PGC673735
- LIGO/Virgo S200213t: No counterpart candidates from Nanshan-0.6m observations
- LIGO/Virgo S200213t: No notable candidates in GOTO imaging
- LIGO/Virgo S200213t: No candidates found in J-GEM follow-up observations
- LIGO/Virgo S200213t: More Candidates from the Zwicky Transient Facility
- LIGO/Virgo S200213t: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200213t: No Counterparts in DDOTI/OAN Optical Observations
- LIGO/Virgo S200213t: MANGROVE catalog galaxy ranking
- LIGO/Virgo S191213g: AT2019wxt Wendelstein optical observations
- LIGO/Virgo S200208q : No significant candidates in TAROT - FRAM - GRANDMA observations
- LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
- LIGO/Virgo S200213t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S200213t : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S200213t: Coverage and upper limits from MAXI/GSC observations
- GRB 200131A: Tautenburg observations
- LIGO/Virgo S200208q: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200208q: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S200208q: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S200208q: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S200208q: No counterpart candidates in HAWC observations
- LIGO/Virgo S200208q : no neutrino counterpart candidate in ANTARES search
- GRB 200208A: Fermi GBM Final Real-time Localization
- Swift J0840.7-3516 (AKA GRB 200205A): Swift-BAT refined analysis
- Swift Trigger 954840 is not a GRB
- GRB 200205B: Swift/UVOT Detection
- GRB 200205B: Swift-XRT refined Analysis
- GRB 200205A = Swift J0840.7-3516, A newly discovered transient X-ray Pulsar
- GRB 200205B: Enhanced Swift-XRT position
- GRB 200205A: Enhanced Swift-XRT position
- GRB 200205B: Swift detection of a burst with optical counterpart
- GRB 200205A: REM optical observations
- MAXI GRB200205.29: Global MASTER-Net observations report
- GRB 200205A: Swift detection of a burst with a possible UV counterpart
- GRB 200131A: Further RATIR Optical Observations
- ZTF20aajnksq: Gemini-North r-band photometry
- GRB 200131A: ISON-Castelgrande optical observations
- GRB 200131A: CDK700 optical observations
- GRB 200131A: Swift/UVOT Detection
- GRB 200131A: VIRT optical transient detection
- GRB 200131A: RATIR Optical Observations
- GRB 200131A: Enhanced Swift-XRT position
- GRB 200131A: Swift detection of a burst with an optical counterpart
- IPN triangulation of GRB 200130B
- LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
- LIGO/Virgo S200128d : No significant candidates in FRAM - TAROT - GRANDMA observations
- LIGO/Virgo S200129m: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S200129m: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200128d: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200128d: no counterpart candidates in the Swift/BAT observations
- Fermi-LAT ANTARES 200127.79 coincidence: MASTER alert observation and presence of young pulsar close to error-box
- GRB 200127A: Swift/UVOT Upper Limits
- GRB 200127A: Mondy optical upper limit
- GRB200127A: Nordic Optical telecope optical upper limit
- LIGO/Virgo S200128d : no neutrino counterpart candidate in ANTARES search
- GRB 200125B: DDOTI/OAN optical observations report
- LIGO/Virgo S200128d: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S200128d: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S200128d: No counterpart candidates in HAWC observations
- GRB 200127A: Nanshan-0.6m optical upper limit
- GRB 200127A: Enhanced Swift-XRT position
- GRB 200127A: AbAO optical upper limit
- GRB 200127A: Swift detection of a burst
- GRB 200125A: Swift/UVOT Upper Limits
- GRB 200125A: Further RATIR Optical Observations and Confirmation of Fading
- GRB 200125A: AbAO optical upper limit
- GRB 200125A: TNG detection of a NIR counterpart candidate
- GRB 200125A: Nanshan-0.6m optical upper limit
- GRB 200125A: RATIR Optical Observations
- GRB 200125A: Enhanced Swift-XRT position
- GRB 200125A: Swift detection of a burst
- LIGO/Virgo S200114f : No significant candidates in TAROT - FRAM - GRANDMA observations
- GRB 200115A: Assy optical observations
- GRB 200122A: Mondy optical upper limit
- GRB 200122A: RATIR Optical Observations
- GRB 200122A: Xinglong-2.16m optical upper limit
- GRB 200122A: Swift/UVOT Upper Limits
- IPN Triangulation of GRB 200120A
- LIGO/Virgo S200115j: Further Swift-XRT sources
- GRB 200122A: GOTO non-detection of optical afterglow
- GRB 200122A: Swift-XRT refined Analysis
- GRB 200122A: Enhanced Swift-XRT position
- GRB 200122A: Swift detection of a burst
- GRB 191031D: XMM-Newton upper limit
- IceCube-200120A: no counterpart candidates in INTEGRAL SPI-ACS and,IBIS prompt observation
- IceCube 200117A: No significant detection in HAWC
- LIGO/Virgo S200115j: GMOS-N upper limits for ZTF20aafqvyc/AT2020yq from the Gemini Observatory
- Fermi-LAT Gamma-ray Observations of IceCube-200117A
- LIGO/Virgo S200115j : No significant candidates in TAROT - FRAM - GRANDMA observations
- LIGO/Virgo S200115j: Mondy upper limits for ZTF20aafqvyc/AT2020yq
- GRB 200115A: Mondy optical observations and correction to GCN 26790
- LIGO/Virgo S200115j: NIR upper limits for ZTF20aafqvyc/AT2020yq from the Palomar 200-inch telescope
- IceCube-200117A: no counterpart candidates in INTEGRAL SPI-ACS and,IBIS prompt observation
- LIGO/Virgo S200114f: No transients found in J-GEM observations of nearby galaxies
- GRB 200115A: AROMA-N Optical Observation
- LIGO/Virgo S200115j: No notable candidates in GOTO imaging
- LIGO/Virgo S200114f: Upper Limits from Wide-Field Infrared Search with Palomar Gattini-IR
- GRB 200115A: DDOTI/OAN optical observations report