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"5820 results found.
- LIGO/Virgo S190503bf: Identification of a GW compact binary merger candidate
- LIGO/Virgo S190412m: Further J-GEM optical/NIR observations
- LIGO/Virgo S190426c: PS1 historical detections and ZTF photometry of Gaia19boq AT2019egk
- Fermi GRB190429.74 Global MASTER-Net observations report
- LIGO/Virgo S190426c: YAHPT Optical Observation
- LIGO/Virgo S190425z: MASTER detection of the faint flare in SDSS Seyfert galaxy z = 0.09
- LIGO/Virgo S190426c: Continued LOAO Observation
- LIGO/Virgo S190425z: MASTER explanation of the nature of an optical flash detected by a Swift as a short flare on a fast-moving WISE brown
- LIGO/Virgo S190426c: LOAO Observation
- LIGO/Virgo S190425z: SVOM/GWAC-F60A observations
- LIGO/Virgo S190426c: DDOTI/OAN Optical Observations
- LIGO/Virgo S190425z: Pre-discovery NIR limits of the UVOT transient candidate from Gattini-IR
- LIGO/Virgo S190426c: RATIR Optical and NIR Observations of Galaxies
- LIGO/Virgo S190426c: COATLI Optical Observations of Galaxies
- GRB 190419A: AstroSat CZTI detection
- LIGO/Virgo S190426c: MMT Follow-Up Observations
- LIGO/Virgo S190426c: Lick/KAIT Follow-Up Observations
- LIGO/Virgo S190426c: Swift-XRT sources
- LIGO/Virgo S190425z: BOOTES-5/JGT observations of galaxies
- LIGO/Virgo S190425z: GRANDMA follow-up observations with Les Makes-T60, AZT-8 and Abastumani-T70
- LIGO/Virgo S190425z: Further MMT Follow-Up Observations
- Baksan Neutrino Observatory Alert 190405.62: Global MASTER-Net:LIGO/Virgo S190425z: PanSTARR OT AT2019ebq/PS19qp
- LIGO/Virgo S190425z: COATLI Observations of Galaxies
- LIGO/Virgo S190425z: RATIR Observations of Galaxies
- LIGO/Virgo S190425z: GROND observations of AT2019ebq/PS19qp
- LIGO/Virgo S190425z: TAROT-GRANDMA observation report
- LIGO/Virgo S190425z: Las Cumbres Observatory Galaxy Targeted Counterpart Search
- LIGO/Virgo S190425z: LWA1 observations
- LIGO/Virgo S190425z: KMTNet Observation
- LIGO/Virgo S190425z: Swope follow-up observations
- LIGO/Virgo S190425z: Pan-STARRS observations and transients in the skymap
- LIGO/Virgo S190425z: KPED Follow-Up Observations
- LIGO/Virgo S190425z: ATLAS observations of the S190425z skymap
- LIGO/Virgo S190425z: ZTF19aarzaod Imaging from Las Cumbres Observatory
- LIGO/Virgo S190425z: J-GEM optical follow-up observations with Subaru/FOCAS
- LIGO/Virgo S190425z: Candidates from the Zwicky Transient Facility
- LIGO/Virgo S190425z: Xinglong/Schmidt follow-up observations
- LIGO/Virgo S190425z: Palomar Gattini-IR wide-field infrared follow-up
- LIGO/Virgo S190425z: SQUEAN Observation
- LIGO/Virgo S190425z: Lick/KAIT Follow-Up Observations
- LIGO/Virgo S190425z: MAXI/GSC Observations
- LIGO/VIRGO S190425z: IceCube Neutrino Search
- LIGO/Virgo S190425z Global MASTER-Net observations report
- Fermi GRB190425.09 Global MASTER-Net observations report
- LIGO/Virgo S190421ar: TAROT-GRANDMA observation report.
- LIGO/Virgo S190421ar: Lick/KAIT Follow-Up Observations
- LIGO/Virgo S190421ar Global MASTER-Net observations report
- Konus-Wind observation of GRB 190415A
- Fermi GRB190420.98 Global MASTER-Net observations report
- Fermi GRB190419.41 Global MASTER-Net observations report
- Fermi Trigger 577360542 / GRB 190419414 / GRB190419A: BALROG localization
- IPN Triangulation of GRB 190415A
- GRB 190415A: Insight-HXMT/HE detection
- Fermi Trigger 576994194 / GRB 190415173 / : BALROG localization
- GRB 190411A: AstroSat CZTI detection
- LIGO/Virgo S190412m: Fermi-LAT search for a high-energy gamma-ray counterpart
- LIGO/Virgo S190408an: Pan-STARRS observations and transients in the skymap
- LIGO/Virgo S190408an: TMTS Optical Observation
- LIGO/Virgo S190408an: DDOTI/OAN Optical Observations
- LIGO/Virgo S190408an: HMT optical observations
- LIGO/Virgo S190408an: SAGUARO follow-up observations
- CORRECTED TARGET NAME: GRB 190408A: MAXI/GSC detection
- GRB 140408A: MAXI/GSC detection
- Search for neutrino counterparts to GW candidate S190408an with IceCube
- GRB 140404B: MAXI/GSC detection
- GRB 190330A: MITSuME Akeno and Okayama optical upper limits
- IceCube-190331A: MASTER optical follow-up observations
- IPN Triangulation of GRB 190329A (long/bright)
- Swift Trigger 895257: Detection of GRO J2058+42 in outburst
- GRB 190326A: Swift detection of a short burst
- Fermi Trigger 575108474 / GRB 190324348: BALROG localization
- Fermi Trigger 574678842 / GRB 190319375: BALROG localization
- Fermi trigger 574140965 / GRB190313.15: MASTER Global Robotic Net optical observation
- GRB190305A: MASTER Global Robotic Net optical observation
- GRB190219A: MASTER Global Robotic Net optical observation
- Trigger 889483: Swift detection of Swift J1858.6-0814
- Trigger 888312: Swift detection of 4U 1901+03
- GRB 190203A: COATLI Optical Observations
- GRB 190204A: Swift detection of a burst with a possible optical counterpart
- GRB 190203A: Swift detection of a burst with an optical counterpart
- GRB 190202A: Swift/UVOT Detection
- GRB 190202A: Koshka Zeiss-1000 optical observations
- GRB 190202A: Swift detection of a burst with an optical counterpart
- GRB 190129B: MASTER Global Robotic Net optical observation
- GRB 190129A: MAXI/GSC detection
- Trigger 886486: Swift detection of MAXI J1631-479
- Trigger 886266: Another Swift trigger on MAXI J1348-630
- Swift Trigger 886157: Swift detection of a new transient Swift J1728.9-3613
- INTEGRAL triggers from 8205 to 8211 are due to MAXI J1348-630, NOT to a GRB
- Swift Trigger 885960: A third Swift trigger on MAXI J1348-630
- Trigger 885845: A second Swift trigger on MAXI J1348-630
- GRB 190123A: IKI-GRB-FuN optical upper limit
- Trigger 884906: Swift detection of MAXI J1631-479
- GRB 190114A: Swift detection of a burst
- GRB 190109B: Fermi GBM observation
- GRB 190109A: Fermi GBM observation
- GRB 190109B: COATLI Optical Observations
- GRB 190109B: Mondy optical upper limit
- INTEGRAL Weak#8189: AROMA-N Optical Observation
- GRB 190109B: Swift detection of a burst