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"
16226 results found.
- GRB 240825A: Swift/UVOT Detection
- GRB 240825A: REM detection of the optical/NIR afterglow
- GRB 240825A: Montarrenti Observatory optical observations
- GRB 240825A: Enhanced Swift-XRT position
- GRB 240825A: LCO optical observations
- SGR 1E 1841-045 / Kes 73 (Trigger 1249878): Osservatorio Atronomico Nastro Verde optical upper limit
- SGR 1E 1841-045 / Kes 73 (Trigger 1249653) - Osservatorio Astronomico Nastro Verde upper limit
- GRB 240824B: NOT optical upper limit
- GRB 240825A: GMG Optical Observation
- 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: SVOM/C-GFT optical upper limit
- GRB 240824B: Swift-XRT afterglow detection
- 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: Skynet Optical Afterglow Discovery
- GRB 240824A: Swift detection of a burst
- SGR 1E 1841-045 / Kes 73: Montarrenti Observatory optical upper limits
- GRB 240821A: Colibri Optical Upper Limit
- EP240820a: PRIME J-band Observations
- GRB 240822A: AstroSat CZTI detection of a short burst
- GRB 240821A: REM optical/NIR upper limits
- GRB 240821A: LCO optical observations
- GRB 240821A: JinShan optical upper limits
- GRB 240809A: Mondy and AbAO Optical Observations
- GRB 240821A: GMG Optical Upper Limit
- GRB 240821A: EP-FXT follow-up observation and afterglow candidates
- GRB 240821A: GRANDMA/LesMakes-T60 Upper Limit
- GRB 240821A : a likely short GRB detected by SVOM/ECLAIRs
- EP240820a: TRT optical upper limit
- EP240820a: EP detection of a fast X-ray transient
- EP240816a: PRIME upper limits
- GRB 240819A : an X-ray transient detected by SVOM/ECLAIRs
- GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
- GRB 240819A: X-ray follow-up observation with EP-FXT
- EP240816b: Liverpool Telescope optical follow-up observations
- GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
- EP240816a: EP detection of a fast X-ray transient and follow-up observation
- EP240816b: TRT optical upper limit
- EP240816b: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
- EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
- LIGO/Virgo/KAGRA S240813c: Identification of a GW compact binary merger candidate
- EP240807a: PRIME H-band upper limits
- GRB 240812B: AstroSat CZTI detection of a long burst
- GRB 240811A: Bassano Bresciano Observatory upper limit
- GRB 240811A: Swift-XRT refined Analysis
- GRB 240811A: Swift/UVOT Upper Limits
- EP240801a: Assy-Turgen optical observations
- GRB 240811A: LCOGT Optical Upper Limit
- GRB 240811A: Enhanced Swift-XRT position
- GRB 240811A: Upper limits with Mephisto
- GRB 240811A: Swift detection of a burst
- GRB 240809A: REM detection of the optical afterglow
- GRB 240809A: Bassano Bresciano Observatory optical observations
- GRB 240809A: GIT afterglow observations
- GRB 240809A: Swift/UVOT Detection
- GRB 240809A: Swift-XRT refined Analysis
- IPN triangulation of GRB 240807A / EP 240807a
- X-ray Transient EP240807a: PRIME near-infrared upper limits
- GRB 240809A: JinShan optical observations
- GRB 240809A: Enhanced Swift-XRT position
- GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
- GRB 240809A: Swift detection of a burst with a bright optical counterpart
- EP-WXT trigger 01709018832: SVOM/C-GFT observations of the star flare
- GRB 240805A: ATCA Radio Upper Limits
- EP240807a/GRB 240807A: EP-FXT detection of the X-ray emission
- EP240806A: Liverpool Telescope optical follow-up observations
- The EP-WXT trigger 01709018832 on August 7th is likely a flaring star
- EP240807a: EP-WXT detection of a fast X-ray transient
- EP240806a: Gemini North-GMOS spectroscopic redshift of z = 2.818
- GRB 240805B: GIT optical upper limit
- EP240806a: LCOGT optical counterpart detection
- GRB 240805B Bassano Bresciano Observatory upper limit
- GRB 240805B: AbAO, CrAO, and Terskol optical upper limits
- EP240806a: EP-FXT detection of the X-ray emission
- EP 240806A: LCO optical observations
- EP240806a: EP-WXT detection of a fast X-ray transient
- GRB 240805B: Optical detection with 1.6m Mephisto
- GRB 240805B: NUTTelA-TAO / BSTI Optical Limits
- GRB 240805B: Swift/UVOT Upper Limits
- GRB 240805A: Swift/UVOT Upper Limits
- GRB 240805B: BTA optical afterglow candidate
- GRB 240805B: Enhanced Swift-XRT position
- GRB 240805B: LCOGT Optical Upper Limits
- GRB 240805B: JinShan optical upper limits
- EP240801a: BTA BVRI photometry
- Swift GRB 240805A: Global MASTER-Net observations report
- GRB 240805A: Swift-XRT refined Analysis
- GRB 240805B: Swift detection of a burst
- EP240801a: Continued optical observations at ZTSh (CraO)
- EP240804a: NOT optical counterpart detection
- EP240804a: EP-WXT detection and EP-FXT follow-up observation of a fast X-ray transient
- EP240802a: Montarrenti Observatory optical upper limit
- EP240801a: Osservatorio Astronomico Nastro Verde upper limit
- EP240802A: Bassano Bresciano Observatory upper limit