GCN Circulars
GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"16290 results found.
- Swift GRB191004.75: Global MASTER-Net OT detection
- LIGO/Virgo S190930t: AT2019rpn, AT2019rpj CrAO continued optical photometry
- GRB 191001A: Swift-XRT observations
- LIGO/Virgo S190930t: J-GEM follow-up observation for Swift J221951-484240
- GRB 191001B: Optical Upper Limits with LCO
- LIGO/Virgo S190930t: Continued Swift/UVOT observations of Swift J221951-484240
- GRB 191001A: Fermi GBM observation
- LIGO/Virgo S190930t: AT2019rpn, AT2019rpj CrAO optical photometry
- IPN triangulation of GRB 191001A
- LIGO/Virgo S190930t: J-GEM follow-up observations for AT2019rpj
- GRB 191001A: KAIT Optical Upper Limit
- GRB 191001A: RATIR Optical and NIR Observations
- LIGO/Virgo S190930t: Lulin Follow-up Observations of AT2019rpn and AT2019rpj
- GRB 191001A: DDOTI Optical Counterpart Candidate
- LIGO/Virgo S190930t and S190930s: MASTER OT J205529.78+220725.5/AT2019rpr further analysis
- LIGO/Virgo S190930t: Upper limits on the two of the ZTF/GROWTH candidates
- GRB 191001B: MITSuME Akeno optical upper limits
- LIGO/Virgo S190923y: optical spectrum of MASTER detected transient
- LIGO/Virgo S190930t and S190930s: MASTER optical observation and optical transient
- GRB 190928A: MASTER optical observations
- GRB 190926A: AbAO upper optical limit
- LIGO/Virgo S190923y: MASTER OT outburst detection inside NSBH merger error-box
- GRB 190926A: MITSuME Akeno optical upper limits
- GRB 190926A: Swift/UVOT Upper Limits
- GRB 190926A: KAIT Optical Upper Limit
- LIGO/Virgo S190814bv: Chandra X-ray non-detection of ASKAP J005547-270433 / AT2019osy
- LIGO/Virgo S190814bv: HST and ALMA observations of the host galaxy of ASKAP J005547-270433 / AT 2019osy
- GRB 190919B: BOOTES-5/JGT and BOOTES-3/YA optical observations
- GRB 190919B: LCO Optical Afterglow Detection
- GRB 190919B: Swift/UVOT Upper Limits
- GRB 190919B: FRAM-Auger optical detection
- GRB 190919B: VLT/X-shooter redshift
- GRB 190919B: MASTER OT early detection at GROND position
- LIGO/Virgo S190814bv: SOAR spectroscopy of AT2019nte host galaxy
- HAWC-190916A: DDOTI Optical Observations
- GRB190915A: MASTER optical observation of BALROG Fermi GRB localization
- LIGO/Virgo S190910h: WHT spectroscopy of Gaia19ebl, Gaia19eba, Gaia19eaz
- LIGO/Virgo S190910d: No Counterparts in DDOTI/OAN Optical Observations
- LIGO/Virgo S190910h: WHT spectroscopy of AT2019pyz/PS19fbi
- LIGO/Virgo S190910h and S190910d: WHT photometry of ZTF candidates
- LIGO/Virgo S190910h: AT2019pxi, AT2019pxj and AT2019pxn 10.4m GTC spectroscopy
- LIGO/Virgo S190910h: WHT spectroscopy of ZTF19abygvmp/AT2019pzg
- LIGO/Virgo S190910h: Four additional candidates from the Zwicky Transient Facility
- LIGO/Virgo S190910d: WHT spectroscopy of ZTF19abyfhov, ZTF19abyfhaq, ZTF19abyfbii
- LIGO/Virgo S190901ap: WHT spectroscopy of Gaia19dzi
- LIGO/Virgo S190910d: AT2019pvu, AT2019pvv, AT2019pvz and AT2019pwa 10.4m GTC spectroscopy
- LIGO/Virgo S190910d: Liverpool Telescope spectroscopy of ZTF19abyfazm
- ZTF19abvizsw: AbAO and CrAO photometry
- GRB 190829A observations in CrAO, photometry of the SN
- LIGO/Virgo S190901ap: ZTF19abwvals is a type-Ia SN near maximum
- LIGO/Virgo S190901ap: Second Epoch Hobby-Eberly Telescope observations of ZTF19abvionh
- GRB 180620A: SEDM Observations
- GRB 190829A optical observation
- LIGO/Virgo S190901ap: NOT spectroscopy of AT2019pjv
- GRB190829A: Keck LRIS spectroscopic confirmation of the accompanying supernova
- LIGO/Virgo S190901ap: No counterpart candidates in KAIT observations
- LIGO/Virgo S190901ap : GRAWITA spectroscopic observation of candidate MASTER OT J171434.95+280725.6
- LIGO/Virgo S190901ap: Dabancheng-0.5m optical observations of AT2019pjv
- GRB 190829A: Liverpool Telescope observations of a slow supernova rise
- ZTF19abvizsw: COATLI Optical Observations
- LIGO/Virgo S190901ap: GOTO optical coverage and detection of AT2019pjv
- GRB190829A: GROND detection of the accompanying SN
- LIGO/Virgo S190901ap: MASTER OT J171434.95+280725.6/AT2019pjv detection
- Liverpool Telescope observations of ZTF19abvizsw, a candidate untriggered GRB afterglow
- GRB 190829A: LCO Optical Afterglow Detection
- GRB 190829A: MeerKAT radio observation
- LIGO/Virgo S190901ap: GROWTH-India follow-up of ZTF19abvionh
- GRB 190829A: Detection of radio afterglow with the uGMRT
- GRB 190829A: Flattening of optical light curve from continued Liverpool Telescope photometry
- LIGO/Virgo S190901ap: Hobby-Eberly Telescope VIRUS observations of ZTF19abvionh
- LIGO/Virgo S190901ap: Hobby-Eberly Telescope VIRUS observations of target galaxy; no obvious optical counterpart.
- LIGO/Virgo S190901ap : GRAWITA spectroscopic observation of candidate ZTFabvixoy
- LIGO/Virgo S190901ap : GRAWITA spectroscopic observation of candidate ZTFabvizsw
- LIGO/Virgo S190814bv : No significant candidates in TAROT-GRANDMA observations
- GRB 190829A: Continued fading inferred from Liverpool Telescope photometry
- LIGO/Virgo S190814bv: SOAR spectroscopy of DECam candidate AT2019ntp
- GRB 190829A: Keck LRIS spectroscopy of the optical afterglow
- GRB 190829A: Liverpool Telescope observations
- LIGO/Virgo S190814bv: AT2019odc and AT2019omt 10.4m GTC spectroscopy
- GRB 190829A: Liverpool Telescope optical photometry
- GRB 190829A: MMT detection of the optical afterglow
- GRB 190829A: KAIT Detection of the Optical Afterglow
- GRB 190829A:: Global MASTER-net optical clear and polarization observations scheduler and some spiculations
- LIGO/Virgo S190814bv: AT2019nqc and AT2019nqz 10.4m GTC spectroscopy
- GRB 190829A: Swift/UVOT detection of an optical afterglow with a rise
- GRB 190829A: GROND detection of the Optical/NIR Afterglow
- GRB 190829A: 10.4m GTC spectroscopy
- GRB 190829A: NOT optical afterglow detection and spectroscopy
- LIGO/Virgo S190828j: No Counterparts in DDOTI/OAN Optical Observations
- GRB 190829A: GROWTH India detection of afterglow
- GRB 190829A:: MASTER-net bright and decay OT detection
- GRB 190829A: Dabancheng-0.5m optical afterglow detection
- GRB 190828B: VLT/X-shooter optical afterglow candidate
- GRB 190828B: optical upper limit from 0.5m Savelli Robotic Telescope
- GRB 190828B: Swift/UVOT Upper Limits
- LIGO/Virgo S190814bv: AT2019nxe and AT2019obc 10.4m GTC spectroscopy
- LIGO/Virgo S190814bv: SOAR spectroscopy of DECam candidates AT2019ntr and AT2019omx
- LIGO/Virgo S190814bv: VLA observation of ASKAP J005547-270433/AT2019osy
- LIGO/Virgo S190814bv: Swift UVOT - no new counterpart candidates identified
- GRB 190828B: Dabancheng-0.5m optical upper limit