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"7447 results found.
- LIGO/Virgo S190512at: Updated sky localization
- LIGO/Virgo S190517h: ANTARES neutrino search
- LIGO/Virgo S190517h: Fermi GBM Observations
- LIGO/Virgo S190517h: HAWC follow-up
- LIGO-Virgo S190517h: AGILE GRID observations
- LIGO/Virgo S190517h: Identification of a GW compact binary merger candidate
- GRB 190515B: Swift detection of a burst
- LIGO/Virgo S190426c: AMI-LA radio observations of ZTF19aassfws
- LIGO/Virgo S190503bf: Gaia Photometric Alerts transient candidate
- LIGO/Virgo S190510g: Gaia Photometric Alerts transient candidate
- LIGO/Virgo S190510g: DECam-GROWTH optical counterpart candidate DG19qcso
- LIGO/Virgo S190513bm: ANTARES neutrino search
- LIGO/Virgo S190513bm: Fermi GBM Observations
- LIGO/Virgo S190510g: Further KMTNet observation of DECam-GROWTH and DESGW candidates
- LIGO/Virgo S190513bm: HAWC follow-up
- LIGO/Virgo S190513bm: Identification of a GW compact binary merger candidate
- LIGO/Virgo S190510g: Pan-STARRS and ATLAS observations and candidates
- LIGO/Virgo S190512at: ANTARES neutrino search
- LIGO/Virgo S190512at: Fermi GBM Observations
- LIGO/Virgo S190510g: Spectroscopic Classification of DECam-GROWTH and DES-GW Candidate DG19fqqk/desgw-190510c with Magellan
- LIGO/Virgo S190512at: Identification of a GW compact binary merger candidate
- IPN triangulation of GRB 190510A (short)
- LIGO/Virgo S190510g: KMTNet observation of DECam-GROWTH and DESGW candidates
- LIGO/Virgo S190510g: OT MASTER142812.05-013615.2 retraction as the kilonova candidate in GCN 24490
- LIGO/Virgo S190510g: MASTER OT detection inside low surface brightness galaxy
- LIGO/Virgo S190510g: Update on candidate significance
- LIGO/Virgo S190510g: DESGW counterpart candidates over 80% of the GW localization area
- LIGO/Virgo S190510g: DESGW counterpart candidate (desgw-190510a)
- LIGO/Virgo S190510g: Pierre Auger Observatory follow-up
- GRB 190511A: Swift detection of a burst
- LIGO/Virgo S190510g: SOAR/Goodman follow-up observations
- LIGO/Virgo S190510g: Optical Counterpart Candidates from DECam-GROWTH
- LIGO/Virgo S190510g: KMTNet observation
- LIGO/Virgo S190510g: CNEOST Follow-Up Observations
- LIGO/Virgo S190510g: Updated classification and data quality report
- LIGO/Virgo S190510g: Lulin Optical Follow-up Observations
- LIGO/Virgo S190425z: CAHA-GRANDMA Observation of the Swift UVOT Source
- LIGO-Virgo S190426c: Pan-STARRS non-detection of ZTF19aassfws
- LIGO-Virgo S190510g: AGILE GRID observations
- LIGO/Virgo S190510g: CLU/NED Galaxies in the Localization Volume
- LIGO/Virgo S190510g: Updated localization from LIGO and Virgo data
- LIGO/Virgo S190510g: ANTARES neutrino search
- LIGO/Virgo S190510g: Identification of a GW compact binary merger candidate
- LIGO/Virgo S190510g: HAWC follow-up
- LIGO/Virgo S190426c: Archival VLASS Observations of ZTF19aassfws 14 days prior to Merger
- GRB 190507B: GOTO optical counterpart search
- LIGO/Virgo S190426c (BHNS candidate): Implications from Numerical Relativity
- IceCube-190504A: MASTER optical monitoring analysis
- LIGO/Virgo S190503bf: AstroSat CZTI upper limits
- LIGO/Virgo S190426c: Update on Source Classification
- Update to the Fermi GBM GCN Reporting
- IceCube-190504A: Swift-XRT Follow-up Observations
- IceCube-190503A: Swift-XRT Follow-up Observations
- LIGO/Virgo S190503bf: CALET Observations
- Search for counterpart to IceCube-190504A with ANTARES
- IceCube-190503A: Lick/KAIT Follow-Up Observations
- IPN triangulation of GRB 190504A (short)
- IceCube-190504A - IceCube observation of a high-energy neutrino candidate event
- LIGO/Virgo S190503bf: ANTARES neutrino search
- LIGO/Virgo S190503bf: Fermi-GBM Observations
- IceCube-190503A - IceCube observation of a high-energy neutrino candidate event
- LIGO/Virgo S190503bf: Identification of a GW compact binary merger candidate
- LIGO/Virgo S190421ar: Updated localization and classification from LIGO and Virgo data
- GRB 190501A: Swift ToO observations
- LIGO/Virgo S190425z: Gaia Photometric Alerts transient candidate
- LIGO/Virgo S190426c: Gaia Photometric Alerts transient candidate
- LIGO/Virgo S190426c: Swift rapid follow-up observations of S190425z and S190426c and URL for observation log for all future events
- LIGO/Virgo S190426c: GROWTH India follow-up of GRAWITA transient
- LIGO/Virgo S190426c: PS1 historical detections and ZTF photometry of Gaia19boq AT2019egk
- LIGO/Virgo S190425z: Gaia Photometric Alerts transient candidate
- LIGO/Virgo S190426c: Gaia Photometric Alerts transient candidate
- LIGO/Virgo S190425z: DECam Observations of the UVOT Candidate Region
- LIGO/Virgo S190425z: VISTA K-band observations of the Swift/UVOT Transient
- LIGO/Virgo S190426c: Additional Candidates from the Zwicky Transient Facility
- LIGO/Virgo S190425z: No i-band detection of the Swift/UVOT transient in SkyMapper observations
- LIGO/Virgo S190425z: No source found at UVOT source location at 6 hrs after LVC report
- LIGO/Virgo S190426c: GROWTH India follow-up
- LIGO/Virgo S190425z: No Optical Detection of the Swift/UVOT Transient in ASAS-SN observations hours before and after discovery
- LIGO/Virgo S190425z: Potential host galaxy of UVOT candidate counterpart found in BLISS
- LIGO/Virgo S190425z: Additional Candidates from the Zwicky Transient Facility
- LIGO/Virgo S190425z: ASAS-SN observations
- LIGO/Virgo S190425z: Pre-discovery NIR limits of the UVOT transient candidate from Gattini-IR
- LIGO/Virgo S190425z: Swift/UVOT and XRT pre-images at the position of the potential Swift/UVOT counterpart
- LIGO/Virgo S190425z: GROWTH-India observations of the Swift/UVOT transient
- LIGO/Virgo S190425z: ZTF photometry of the UVOT transient candidate hours before discovery
- LIGO/Virgo S190426c: J-GEM optical/NIR follow-up observations
- LIGO/Virgo S190425z: Transient found in Swift/UVOT counterpart search
- LIGO/Virgo S190426c: GOTO optical coverage - no notable counterparts
- LIGO/Virgo S190426c: Optical Wide-field Search with the Zwicky Transient Facility
- LIGO/Virgo S190426c: Updated localization from LIGO and Virgo data
- LIGO/Virgo S190426c: CALET Observations
- LIGO/Virgo S190425z: Lulin Observations of Counterpart Search
- ANTARES follow-up of the GW candidate S190426c
- LIGO/Virgo S190425z - ePESSTO+ spectrum of candidate PS19qu
- LIGO/Virgo S190425z: ANU 2.3m early observations of ZTF19aarykkb
- LIGO/Virgo S190426c: GROWTH India follow-up
- LIGO/Virgo S190426c: STARE2 simultaneous L-band radio observations
- LIGO/Virgo S190426c: a possible lensed NS-NS merger
- LIGO/Virgo S190426c: Tentative Red Transient Candidate from Las Cumbres Observatory
- LIGO/Virgo S190426c: Fermi GBM Observations