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"22207 results found.
- GRB 240513A: Tiled Swift observations
- LAT GRB240513.31: Global MASTER-Net observations report
- Fermi GRB 240513B: Global MASTER-Net observations report
- Fermi trigger No 737277727: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240513cx: Coverage and upper limits from MAXI/GSC observations
- Fermi trigger No 737258655: Global MASTER-Net observations report
- GRB 240511A: J-band observations with WINTER
- Fermi trigger No 737247400: Global MASTER-Net observations report
- Fermi trigger No 737244199: Global MASTER-Net observations report
- Fermi trigger No 737218721: Global MASTER-Net observations report
- Fermi trigger No 737196587: Global MASTER-Net observations report
- Fermi trigger No 737168073: Global MASTER-Net observations report
- GRB 240511A: optical afterglow detection from the NOT
- Fermi trigger No 737173236: Global MASTER-Net observations report
- Fermi GRB 240511A: Global MASTER-Net observations report
- Swift GRB 240511A: Global MASTER-Net observations report
- Fermi trigger No 737105243: Global MASTER-Net observations report
- Fermi trigger No 737152719: Global MASTER-Net observations report
- Fermi trigger No 737102480: Global MASTER-Net observations report
- Fermi trigger No 737111207: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240422ed: GMOS-S photometry of J-GEM24a
- LIGO/Virgo/KAGRA S240422ed: P200 observations of AT2024hit
- LIGO/Virgo/KAGRA S240422ed: Candidates from the latest GW-MMADS DECam Observations
- Fermi trigger No 736967879: Global MASTER-Net observations report
- EP240506a: CrAO ZTSH optical upper limit
- EP240506a: Archival radio searching
- EP240506a: TRT optical upper limit
- Fermi trigger No 736733320: Global MASTER-Net observations report
- EP240506a: Optical upper limit with Kinder observations
- EP240506a: EP-WXT detection of a new fast X-ray transient
- LIGO/Virgo/KAGRA S240422ed: Additional WINTER near-infrared J-band observations
- LIGO/Virgo/KAGRA S240422ed: Swope Follow-up of AT2024hfr and AT2024hfs
- GRB 240504A: Swift/BAT-GUANO detection of a burst outside the coded FOV
- Fermi trigger No 736564880: Global MASTER-Net observations report
- IceCube-240424A: GRANDMA Optical Upper Limit of Fermi J2151.3+0220
- GRB 240502C: Zeiss-1000 at Koshka observatory observations of GOTO optical counterpart candidates
- Fermi trigger No 736461232: Global MASTER-Net observations report
- Fermi GRB 240504A: Global MASTER-Net observations report
- Fermi trigger No 736472503: Global MASTER-Net observations report
- GW170817: VLA observations at ~5.5 yrs since merger
- Fermi trigger No 736387941: Global MASTER-Net observations report
- LXT 240402A / GRB 240402B: VLT X-shooter redshift of host
- GRB 240502A: GOTO optical upper limit
- Fermi trigger No 736379109: Global MASTER-Net observations report
- GRB 240502C: GOTO possible optical counterpart candidates
- Fermi GRB 240502B: Global MASTER-Net observations report
- Fermi GRB 240502A: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet Transient Candidates
- Integral GRB240502.23: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240422ed: Host redshifts of AT2024hfq, AT2024hfu, and AT2024hmo from DBSP
- Fermi GRB 240501A: Global MASTER-Net observations report
- Fermi trigger No 736197684: Global MASTER-Net observations report
- MeerKAT Discovery of a Probable Radio Counterpart to EP240414a
- LIGO/Virgo/KAGRA S240422ed: GECKO/7DT ToO observations
- Additional DECam GW-MMADS Candidates from three nights of observations
- Fermi-LAT gamma-ray observations of IceCube-240424A
- LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limit for EP240426a
- LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet ToO observations
- LIGO/Virgo/KAGRA S240422ed: ENGRAVE VLT/XShooter spectroscopy of the host galaxy of J-GEM24a
- Fermi GRB 240428A: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240422ed: J-band non-detection of J-GEM24a
- LIGO/Virgo/KAGRA S240422ed: DDOTI Optical Upper Limit for J-GEM24a
- LIGO/Virgo/KAGRA S240422ed: Observations with 1.6m Mephisto
- LIGO/Virgo/KAGRA S240422ed: A transient discovered from Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
- LIGO/Virgo/KAGRA S240422ed: NOT optical observations of EP240426a
- EP240426b: EP-WXT detection of a new fast X-ray transient
- LIGO/Virgo/KAGRA S240422ed: Archival radio detection of EP240426a
- LIGO/Virgo/KAGRA S240422ed: Swope Follow-up of AT2024hfq, AT2024hfr, AT2024hfs, and AT2024hfx
- LIGO/Virgo/KAGRA S240422ed: GRANDMA Optical Upper Limits for EP240426a
- LIGO/VIRGO/KAGRA S240422ed: Historical variability for EP240426a
- GRB 240414A: NOEMA detection
- LIGO/Virgo/KAGRA S240422ed: EP240426a possible optical detection
- LIGO/Virgo/KAGRA S240422ed: Continued Magellan Observations
- LVK S240422ed: Further Swift-XRT followup of three sources
- LIGO/Virgo/KAGRA S240422ed: Magellan Follow-up Observations of Swift/XRT candidates
- LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility contuinued observations of S240422ed and candidate analysis
- LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search update and AT2024hfx, AT2024hgl observations
- S240422ed: BlackGEM/MeerLICHT transient detection AT2024hgl/MLTJ080628.10-250116.4
- LIGO/Virgo/KAGRA S240422ed: PRIME near-infrared observations
- LIGO/Virgo/KAGRA S240422ed: 2.5m PRL Telescope follow-up of the Swift/XRT source S240422ed_X190
- S240422ed: MeerLICHT/BlackGEM photometry on AT2024hfx and archival ZTF detection
- LIGO/Virgo/KAGRA S240422ed: Second night Pan-STARRS observations of the skymap
- LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
- LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-FXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
- LIGO/Virgo/KAGRA S240422ed: Upper limits from GECAM Observations
- LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA and Kilonova-Catcher galaxy targeting observations
- LIGO/Virgo/KAGRA S240422ed: Additional DECam GW-MMADS Candidates from the first two nights of observations
- LIGO/Virgo/KAGRA S240422ed: ANU 2.3m followup of candidate counterparts
- LIGO/Virgo/KAGRA S240422ed: Magellan Spectrum of GW-MMADS Candidate AT2024hdo Indicates a Type II SN
- Fermi trigger No 735697285: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S240422ed: SRG/eROSITA archival upper limits for Swift/XRT candidates
- LIGO/Virgo/KAGRA S240422ed: Himalayan Chandra Telescope follow-up of the Swift/XRT source S240422ed_X101
- LIGO/Virgo/KAGRA S240422ed: No significant counterpart candidates in HAWC observations
- LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
- LIGO/Virgo/KAGRA S240422ed: X-ray Upper Limits from EP-WXT for the Potential Electromagnetic Counterparts Reported by Swift and DECam
- LIGO/Virgo/KAGRA S240422ed: MOSFIRE spectroscopy of the DECam GW-MMADS candidate AT 2024hdn
- LIGO/Virgo/KAGRA S240422ed: ATCA follow-up of candidate counterparts
- LIGO/Virgo/KAGRA S240422ed: MOSFIRE imaging of the DECam GW-MMADS candidate AT 2024hdm
- LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
- LIGO/Virgo/KAGRA S240422ed: Early X-ray Upper Limits from EP-WXT for the LVK Sky Localization Region