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.
Lucene Examples (click to copy):
subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"
19124 results found.
- GRB 241002B: ULL-ASTRO-MASTER LCOGT 0.4m + QHY600 detection of the GOTO optical counterpart candidate AT 2024xbg / GOTO24gpc
- GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
- GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
- GRB 241002C : MITSuME Akeno optical upper limits
- GRB241001A: REM optical/NIR upper limits
- GRB 241002A: Swift/UVOT Upper Limits
- EP240930a: Liverpool Telescope observations
- GRB 241002A: LCOGT Optical Upper Limits
- GRB 241001A: GRANDMA and Kilonova-Catcher optical afterglow detection and upper limits
- GRB 241001A: Swift/UVOT Detection
- GRB 241002B: GOTO optical counterpart candidate
- GRB 241002C : Detection of a long soft transient by SVOM/ECLAIRs
- GRB 240929A: Liverpool Telescope prompt followup observations
- GRB 241001A: Swift-XRT observations
- GRB241001A: optical afterglow candidate
- GRB 241002A: Enhanced Swift-XRT position
- LIGO/Virgo/KAGRA S241002e: Identification of a GW compact binary merger candidate
- GRB 241002A: Swift detection of a burst
- GRB 240930B: Fermi GBM Observation
- GRB 240930B: GRBAlpha detection
- GRB 240929A: GRBAlpha detection
- GRB 241001A : Detection of a soft transient by ECLAIRs onboard SVOM
- GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
- EP240930a: GOTO optical upper limits
- EP240930a: EP-WXT detection of a fast X-ray transient
- LIGO/Virgo/KAGRA S240930du: Identification of a GW compact binary merger candidate
- GRB 240929A : Leavitt Observatory optical upper limit
- GRB 240825A: LBT optical observations
- LIGO/Virgo/KAGRA S240930aa: Identification of a GW compact binary merger candidate
- GRB 240929A long GRB detected by INTEGRAL
- Konus-Wind detection of GRB 240912A
- Swift Trigger 1256950 is probably not a GRB
- LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240920dw: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240919bn: Upper limits from Swift/BAT-GUANO
- NuEm-240926A / IC240926A: BZQJ0955+4532 ~0.6m optical decay and rebrightening detection by MASTER
- EP trigger ID 01709061302: the X-ray transient is likely a stellar flare event
- Konus-Wind detection of GRB 240905B
- EP240919a / GRB 240919A: SVOM/VT upper limit
- LIGO/Virgo/KAGRA S240925n: Updated Sky localization and Source Classification
- Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
- GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
- LIGO/Virgo/KAGRA S240925n: Identification of a GW compact binary merger candidate
- GRB 240905B: VZLUSAT-2 detection
- LIGO/Virgo/KAGRA S240924a: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240923ct: Identification of a GW compact binary merger candidate
- GRB 240918B: AstroSat CZTI detection
- LIGO/Virgo/KAGRA S240922df: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240921cw: Identification of a GW compact binary merger candidate
- EP240913A/GRB 240913C: AbAO optical upper limit
- EP240919a / GRB 240919A: Mondy optical upper limit
- EP240913a/GRB 240913C: 1.6m Mephisto observations
- EP240918a: SVOM/VT upper limit
- Fermi GBM Sub-Threshold Detection of GRB240919A / EP240919a
- EP240919a / GRB 240919A: REM optical and NIR upper limits
- EP240918b and EP240918c: Optical upper limits with Kinder observations
- GRB 240414A: further radio observations with the VLA
- EP240919a: Optical upper limit with Kinder observations
- LIGO/Virgo/KAGRA S240920dw: Identification of a GW compact binary merger candidate
- GRB 240910A: radio detection with the VLA
- EP240918a: 1.6m Mephisto multi-band Optical Upper Limit
- EP240919a: NOT and Gemini optical observations
- EP240919a: GOTO optical upper limits
- EP240919a: JinShan optical upper limits
- LIGO/Virgo/KAGRA S240920bz: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240917cb: Updated Sky localization and EM Bright Classification
- LIGO/Virgo/KAGRA S240916ar: Updated Sky localization and EM Bright Classification
- GRB 240910A: further Swift observations and confirmation of afterglow
- LIGO/Virgo/KAGRA S240919bn: Identification of a GW compact binary merger candidate
- EP240918a: JinShan optical upper limits
- EP240918a: YAHPT Optical Upper Limit
- EP240918a: Optical upper limits with Kinder observations
- EP240918a: GMG Optical Upper Limit
- GRB 240916A: GRBAlpha detection
- GRB 240914B: GRBAlpha detection
- EP240918a: an X-ray transient detected by Einstein Probe
- IPN triangulation of GRB 240913C / EP 240913a
- LIGO/Virgo/KAGRA S240917cb: Identification of a GW compact binary merger candidate
- GRB 240821A: radio observation with the VLA
- GRB 240916A: Swift-XRT afterglow detection
- LIGO/Virgo/KAGRA S240916ar: Identification of a GW compact binary merger candidate
- GRB 240916A: GOTO identification of two new optical sources within the GBM localisation region
- EP240913a: VLT/HAWK-I near-infrared upper limits
- LIGO/Virgo/KAGRA S240915bd: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S240915b: Updated Sky localization and EM Bright Classification
- LIGO/Virgo/KAGRA S240915b: Identification of a GW compact binary merger candidate
- GRB 240914A: Swift-XRT observations
- GRB 240914B: AstroSat CZTI detection
- EP240913A / GRB 240913C: AstroSat CZTI detection
- GRB 240910A: SVOM/VT optical observations
- EP240913a: NOT optical upper limits
- EP240913a: JinShan optical upper limits
- EP240913a: ESO-NTT optical observations
- GRB 240914A: ESO-NTT optical observations
- GRB 240905E: further NOT optical observations
- EP240913a: A GRB Event
- EP240913a: EP-WXT detection of a fast X-ray transient
- GRB 240911A: LCO optical observations
- GRB 240911A: JinShan optical upper limits on two Swift/XRT candidates
- GRB 240912A: Swift/UVOT Detection