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.
Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
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"21392 results found.
- GRB 240905E: CrAO Optical Afterglow observations, possible OT candidate
- GRB 240905E: AKO Optical Upper Limit
- GRB 240905E: SVOM/C-GFT optical upper limit
- GRB 240905E: OHP/MISTRAL T193 optical upper limit
- GRB 240905E: NOT optical upper limits
- GRB 240905E: REM optical/NIR upper limits
- GRB 240905E: Swift-XRT refined Analysis
- GRB 240905E: SVOM/GRM observation
- GRB 240905E: LCOGT Optical Upper Limit
- GRB 240905E: Swift/UVOT Upper Limits
- GRB 240905E: SAO RAS optical upper limit
- GRB 240905E: Nanshan/HMT optical upper limit
- Swift GRB 240905E: Global MASTER-Net observations report
- GRB 240905E: Swift detection of a burst
- GRB 240819A: Optical upper limits from TESS
- Swift GRB 240904A: Global MASTER-Net observations report
- GRB 240904A: Swift detection of a burst
- LIGO/Virgo/KAGRA S240825ar: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240807h: Upper limits from Swift/BAT-GUANO
- GRB 240828A: GECAM detection
- GRB 240825A: MeerLICHT afterglow detection
- GRB240828B: REM optical/NIR upper limits
- GRB 240828B: AbAO optical upper limit
- GRB 240828B: Mephisto optical upper limit
- GRB 240828B: GRANDMA Optical Upper Limit
- GRB 240829A: Swift-BAT refined analysis
- GRB 240825A: Swift-BAT refined analysis
- GRB 240828B: J-band upper limit from WINTER
- GRB 240828B: GMG Optical Upper Limit
- GRB 240828B: SAO RAS optical upper limit
- GRB 240828B: KAIT optical upper limit
- GRB 240828A: Fermi GBM Observation
- GRB 240828A: KAIT Optical Afterglow Candidate
- GRB 240828A: Swift-XRT afterglow detection
- GRB 240828B: Swift-XRT afterglow detection
- GRB 240829A: Swift detection of a burst
- Swift GRB240829.16: Global MASTER-Net observations report
- GRB 240828A: Fermi-LAT detection
- GRB 240828A: Tiled Swift observations
- GRB 240825A: Upper limits from a neutrino search with IceCube
- GRB 240819A as a likely X-Ray Flash
- GRB 240828B: Swift ToO observations
- GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
- GRB 240825A: GECAM detection
- GRB 240824A: GIT optical upper limit
- GRB 240819A: Swift afterglow confirmation
- GRB 240824B: Ondrejov D50 optical limit
- GRB 240825A: PRIME near-infrared detection
- Konus-Wind detection of GRB 240825A (bright/long)
- GRB 240825A: Fermi GBM Observation
- GRB 240825A: AKO Optical Follow-Up Observations
- GRB 240825A: AstroSat CZTI detection of the long bright burst
- SGR 1E 1841-045 / Kes 73: SVOM/GRM observation
- GRB 240825A: Swift/UVOT Detection
- GRB 240825A: REM detection of the optical/NIR afterglow
- GRB 240825A: Swift-XRT refined Analysis
- GRB 240825A: VLT/X-shooter redshift
- GRB 240825A: SVOM/C-GFT optical observations
- GRB 240825A: Montarrenti Observatory optical observations
- GRB 240825A: Enhanced Swift-XRT position
- GRB 240825A: MASTER optical counterpart observation
- GRB 240825A: Fermi-LAT detection
- GRB 240825A: LCO optical observations
- GRB 240824B: KAIT optical upper limit
- GRB 240824B: Fermi GBM Observation
- GRB 240825A: GMG Optical Observation
- Swift GRB 240825A: Global MASTER-Net observations report
- GRB 240825A: 1.6m Mephisto multi-band detection
- GRB 240825A: AKO Optical Afterglow Detection
- GRB 240825A: Skynet Optical Afterglow observations
- GRB 240825A: Nanshan/HMT optical afterglow observations
- GRB 240825A: Swift detection of a burst with a bright optical counterpart
- GRB 240824A: Swift-BAT refined analysis
- GRB 240824A: SVOM/C-GFT optical upper limit
- GRB 240824B: Swift-XRT afterglow detection
- GRB 240824A: Swift-XRT observations
- GRB 240824B: Swift/BAT arcminute localization of a burst
- GRB 240824B: Swift ToO observations
- GRB 240824A: Swift/UVOT Upper Limits
- GRB 240821A: Swift/UVOT observations of the XRT sources.
- GRB240824A: GRANDMA/TAROT-TCA Upper Limit
- SGR 1E 1841-045 / Kes 73: Leavitt Observatory optical upper limit
- GRB 240824A: KAIT optical upper limit
- GRB 240824A: Skynet Optical Afterglow Discovery
- GRB 240824A: Swift detection of a burst
- Swift GRB240824.04: Global MASTER-Net observations report
- SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
- GRB 240821A: Colibri Optical Upper Limit
- GRB 240821A: Swift-XRT observations
- GRB 240821A: REM optical/NIR upper limits
- GRB 240821A: JinShan optical upper limits
- GRB 240809A: Mondy and AbAO Optical Observations
- GRB 240821A: SVOM/VT follow-up and optical upper limit
- GRB 240821A: GMG Optical Upper Limit
- GECAM-B observation of a short burst from SGR 1E 1841-045 / Kes 73
- GRB 240821A: Swift ToO observations
- Fermi-GBM Observations of the reactivation of SGR 1E 1841-045 / Kes 73
- Trigger 1249878: Swift detection of another burst from SGR 1E 1841-045 / Kes 73
- GRB 240819A: Swift-XRT observations
- GRB 240819A: JinShan optical upper limits on one Swift/XRT source