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"21106 results found.
- GRB 191004B: Optical Afterglow Detection with LCO
- Swift GRB191004.9: 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
- 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
- IceCube-191001A: Candidate Counterparts with the Zwicky Transient Facility
- IceCube-191001A: Not observable by Fermi-GBM
- GRB 191001A: Swift ToO observations
- LIGO/Virgo S190930t: Candidates from ATLAS observations and constraints on AT2019rpr and AT2019rpn
- 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: HCT observations of ZTF19acbpsuf
- LIGO/Virgo S190930t: Lulin Follow-up Observations of AT2019rpn and AT2019rpj
- LIGO/Virgo S190930s: no counterpart candidates in SAGUARO/CSS observations
- LIGO/Virgo S190930s: No counterpart candidates in KAIT observations
- GRB 191001A: DDOTI Optical Counterpart Candidate
- IceCube Alert 191001.84: Global MASTER-Net observations report
- LIGO/Virgo S190930t: Upper limits on the two of the ZTF/GROWTH candidates
- LIGO/Virgo S190814bv: VLA 6 GHz observations of 75 galaxies in the 90% localization region
- GRB 191001B: Swift detection of a burst
- LIGO/Virgo S190930t and S190930s: MASTER PSN in unknown disk galaxy
- LIGO/Virgo S190930t: Candidates from the Zwicky Transient Facility
- LIGO/Virgo S190930t: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190930t and S190930s: MASTER optical observation and optical transient
- Fermi trigger No 591604915: Global MASTER-Net observations report
- LIGO/Virgo S190930s: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190930t: Upper limits from CALET observations.
- LIGO/Virgo S190930s: Upper limits from CALET observations.
- 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 S190930s: No counterpart candidates in AGILE-MCAL observations
- LIGO/Virgo S190930s: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S190930t: Global MASTER-Net observations report
- LIGO/Virgo S190930s: Global MASTER-Net observations report
- Fermi trigger No 591532362: Global MASTER-Net observations report
- GRB 190928A: MASTER optical observations
- Fermi trigger No 591391412: Global MASTER-Net observations report
- Baksan Neutrino Observatory Alert 190928.37: Global MASTER-Net observations report
- Fermi trigger No 591321287: Global MASTER-Net observations report
- GRB 190926A: Upper Limit from OSN T150 Observation
- LIGO/Virgo S190923y: MASTER OT outburst detection inside NSBH merger error-box
- GRB 190926A: Swift/UVOT Upper Limits
- GRB 190926A: KAIT Optical Upper Limit
- Swift GRB190926.41: Global MASTER-Net observations report
- 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: no counterpart candidates in the Swift/BAT observations
- 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: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo S190923y: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190924h: Global MASTER-Net observations report
- LIGO/Virgo S190923y: Upper limits from CALET observations.
- Fermi-LAT Gamma-ray Observations of IceCube-190922A
- LIGO/Virgo S190923y: INTEGRAL IBIS coded-masked imaging observations of part of the localization area and further all-sky upper limits
- IceCube-190922B: Identification of a Candidate Supernova from the Zwicky Transient Facility
- 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
- 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 counterpart candidates in HAWC observations
- LIGO/Virgo S190923y: Global MASTER-Net observations report
- Fermi trigger No 590899086: Global MASTER-Net observations report
- IceCube-190922B: INTEGRAL was inactive at the time of the event
- IceCube-190922B: Upper limits from Fermi-GBM Observations
- IceCube-190922A: Upper limits from Fermi-GBM Observations
- IceCube Alert 190922.96: Global MASTER-Net observations report
- LIGO/Virgo S190814bv: HST and ALMA observations of the host galaxy of ASKAP J005547-270433 / AT 2019osy
- Fermi trigger No 590777160: Global MASTER-Net observations report
- GRB 190919B: BOOTES-5/JGT and BOOTES-3/YA optical observations
- Baksan Neutrino Observatory Alert 190920.65: Global MASTER-Net observations report
- GRB 190919B: LCO Optical Afterglow Detection
- GRB 190919B: Swift/UVOT Upper Limits
- GRB 190919B: Swift-XRT observations
- GRB 190919B: MASTER OT early detection at GROND position
- GRB 190919B: Swift ToO observations
- GRB 190919B: GROND detection of the NIR afterglow
- Integral GRB190919.99: Global MASTER-Net observations report
- Fermi trigger No 590621700: Global MASTER-Net observations report
- Fermi trigger No 590610007: Global MASTER-Net observations report
- LIGO/Virgo S190814bv: SOAR spectroscopy of AT2019nte host galaxy
- LIGO/Virgo S190915ak: No significant candidates in TAROT-GRANDMA observations
- LIGO/Virgo S190910h: No significant candidates in TAROT-GRANDMA observations
- NASA GW-EM Community Survey
- HAWC-190916A: Upper limits from Insight-HXMT/HE observations