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"28045 results found.
- GRB 191004B: GROND Detection of the Optical/NIR Afterglow
- GRB 191004A: GROND Upper limits
- GRB 191004B: COATLI Optical Observations
- GRB 191004A: Swift-XRT refined Analysis
- GRB 191004B: Swift-BAT refined analysis
- GRB 191004B: NOT optical photometry
- GRB 191004A: Swift-BAT refined analysis
- GRB 191004A: NOT optical upper limits
- GRB 191004B: Enhanced Swift-XRT position
- GRB 191004A: Enhanced Swift-XRT position
- GRB 191004B: Optical Afterglow Detection with LCO
- Swift GRB191004.9: Global MASTER-Net OT detection
- GRB 191004B: Swift detection of a burst with an optical counterpart
- GRB 191004A: Swift detection of a burst with an optical detection
- Swift GRB191004.75: Global MASTER-Net OT detection
- GRB 191001A: Swift-XRT observations
- GRB 191001B: Optical Upper Limits with LCO
- LIGO/Virgo S190930t: Continued Swift/UVOT observations of Swift J221951-484240
- GRB 191001A: Fermi GBM observation
- GRB 190926A: Upper limit from CAHA 2.2m observation
- IceCube-191001A: HAWC follow-up
- LIGO/Virgo S190930t: Upper limits from Insight-HXMT/HE observations
- LIGO/Virgo S190930s: Upper limits from Insight-HXMT/HE observations
- Fermi-LAT Gamma-ray Observations of IceCube-191001A
- GRB 191001B: Swift-BAT refined analysis
- IPN triangulation of GRB 191001A
- LIGO/Virgo S190930t: No neutrino candidates at Pierre Auger Observatory
- LIGO/Virgo S190930t: Candidates from ATLAS observations and constraints on AT2019rpr and AT2019rpn
- GRB 191001A: RATIR Optical and NIR Observations
- LIGO/Virgo S190930s: no counterpart candidates in SAGUARO/CSS observations
- IceCube-191001A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 191001A: DDOTI Optical Counterpart Candidate
- LIGO/Virgo S190924h: Correction to GCN 25905, updated sky localization for S190924h
- LIGO/Virgo S190828h: Updated Sky Localization
- LIGO/Virgo S190923y: optical spectrum of MASTER detected transient
- LIGO/Virgo S190930t: Transient found in Swift/UVOT counterpart search
- LIGO/Virgo S190930t: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190930s: No counterpart candidates in Fermi-LAT observations
- GRB 191001A: BALROG localization (Fermi Trigger 591604915 / GRB 191001279)
- GRB 191001A: Fermi GBM Final Real-time Localization
- LIGO/Virgo S190930t: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S190930s: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S190930t: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S190930t: Upper limits from Fermi-GBM Observations
- LIGO/Virgo S190930s: Upper limits from Fermi-GBM Observations
- LIGO/Virgo S190930t: No counterpart candidates in HAWC observations
- LIGO/Virgo S190930s: no counterpart candidates in AGILE-GRID observations
- LIGO/Virgo S190928c: Retraction of GW unmodeled transient candidate
- LIGO/Virgo S190930t : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S190930s : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S190930t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 190928A: Insight-HXMT/HE detection
- LIGO/Virgo S190930s: No counterpart candidates in AGILE-MCAL observations
- LIGO/Virgo S190930s: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S190930t: Identification of a GW compact binary merger candidate
- LIGO/Virgo S190930t: Upper limits from IceCube neutrino searches
- LIGO/Virgo S190930s: Upper limits from IceCube neutrino searches
- LIGO/Virgo S190930s: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190930s: Identification of a GW compact binary merger candidate
- GRB 190928A: MASTER optical observations
- GRB 190926A: AbAO upper optical limit
- LIGO/Virgo S190828j: Updated Sky Localization
- GRB 190926A: Swift-BAT refined analysis
- GRB 190926A: Upper Limit from OSN T150 Observation
- GRB 190926A: Swift/UVOT Upper Limits
- GRB 190926A: Swift-XRT refined Analysis
- GRB 190926A: Enhanced Swift-XRT position
- GRB 190926A: Swift detection of a burst
- LIGO/Virgo S190923y: No significant candidates in TAROT-GRANDMA observations
- LIGO/Virgo S190923y: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S190924h: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190924h: Not observable by CALET
- LIGO/Virgo S190924h: no counterpart candidates in the Swift/BAT observations
- LIGO/Virgo S190923y: No neutrino candidates at Pierre Auger Observatory
- LIGO/Virgo S190924h: Upper limits from Fermi-GBM Observations
- LIGO/Virgo S190924h: no counterpart candidates in AGILE-GRID observations
- LIGO/Virgo S190924h: No counterpart candidates in AGILE-MCAL observations
- Fermi-LAT Gamma-ray Observations of IceCube-190922B
- LIGO/Virgo S190924h: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- LIGO/Virgo S190924h : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S190924h: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S190923y: No counterpart candidates in Fermi-LAT observations
- IceCube-190922B: Upper limits from a search for additional neutrino events in IceCube
- LIGO/Virgo S190924h: Identification of a GW compact binary merger candidate
- LIGO/Virgo S190924h: Upper limits from IceCube neutrino searches
- Fermi-LAT Gamma-ray Observations of IceCube-190922A
- IceCube-190922B - HAWC follow-up
- LIGO/Virgo S190923y: INTEGRAL IBIS coded-masked imaging observations of part of the localization area and further all-sky upper limits
- LIGO/Virgo S190923y: Upper limits from Fermi-GBM Observations
- LIGO/Virgo S190814bv: Chandra X-ray non-detection of ASKAP J005547-270433 / AT2019osy
- LIGO/Virgo S190923y: Upper limits from AGILE-GRID observations
- GRB 190923A: BALROG localization (Fermi Trigger 590942887 / GRB 190923617)
- LIGO/Virgo S190923y: No counterpart candidates in AGILE-MCAL observations
- LIGO/Virgo S190923y: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S190923y : no neutrino counterpart candidate in ANTARES search
- LIGO/Virgo S190923y: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190923y: Identification of a GW compact binary merger candidate
- LIGO/Virgo S190923y: No counterpart candidates in HAWC observations
- LIGO/Virgo S190923y: Upper limits from IceCube neutrino searches
- IceCube-190922A: Upper limits from Fermi-GBM Observations