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"27776 results found.
- GRB240713A: X-ray follow-up observation with EP-FXT
- GRB 240713B: AstroSat CZTI detection of a long burst
- GRB240713A : The first probable GRB Located on-Board SVOM by ECLAIRs
- EP240708a: GSP optical upper limit
- GRB 240712A: Swift detection of a burst
- GRB 240711A: Fermi GBM Final Real-time Localization
- GRB 240710A: Fermi GBM Final Real-time Localization
- EP240708a: NOT optical observations
- EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
- EP240708a: EP-WXT detection of a fast X-ray transient
- LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
- EP240703b: GSP optical upper limit
- GRB 240705A: Fermi GBM Final Real-time Localization
- Konus-Wind detection of GRB 240627A
- IPN triangulation of GRB 240628B (short)
- EP240703a and EP240703b: Swift/XRT upper limits
- EP240703c: Kinder optical follow-up and Swift XRT observations
- EP240703a: BOOTES-3 optical upper limit
- EP240703a: Liverpool Telescope optical follow-up observations
- EP240703c: EP-WXT detection of an X-ray transient
- IPN triangulation of GRB 240627A
- GRB 240619A: Host galaxy redshift from VLT/X-shooter
- The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
- EP240703b: EP-WXT detection of a fast X-ray transient
- Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
- EP240702a: Swift/XRT upper limit
- EP240703a: EP-WXT detection of a fast X-ray transient
- EP240702a: GSP optical upper limit
- GRB 240702A: Fermi GBM Final Real-time Localization
- EP240702a: EP-WXT detection of a fast X-ray transient
- LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
- GRB 240627A: CALET Gamma-Ray Burst Monitor detection
- LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
- GRB 240629A: Fermi GBM Final Real-time Localization
- IPN triangulation of GRB 240619C
- GRB 240627A: NuSTAR Detection of the long GRB
- GRB 240615A: SAI CMO J- band observations
- GRB 240627A: AstroSat CZTI detection
- EP240626a: EP-FXT detection of the X-ray emission
- GRB 240624A: Swift-BAT refined analysis
- Konus-Wind detection of GRB 240619A
- EP240626a: BOOTES-7 optical upper limit
- EP240626a: EP-WXT detection of a fast X-ray transient
- GRB 240624B: CALET Gamma-Ray Burst Monitor detection
- GRB 240625B: Fermi GBM Final Real-time Localization
- EP240625a: EP-FXT detection of the X-ray emission
- GRB 240624B: GRBAlpha detection
- GRB 240625A: Fermi GBM Final Real-time Localization
- EP240625a: EP-WXT detection of a fast X-ray transient
- GRB240624A: Fermi GBM Observation
- LIGO/Virgo/KAGRA S240622h: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240621dy: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240618ah: Upper limits from Swift/BAT-GUANO
- Swift GRB 240624A: Global MASTER-Net observations report
- GRB 240624B: Fermi GBM Final Real-time Localization
- GRB 240624A: Fermi GBM Final Real-time Localization
- GRB 240619A: detection of a radio counterpart with AMI-LA
- GRB 240624A: Swift detection of a burst
- LIGO/Virgo/KAGRA S240623dg: Retraction of GW compact binary merger candidate
- GRB 240619A: J-band detection with WINTER (duplicate submission of GCN 36739)
- GRB 240619A: J-band detection with WINTER
- GRB 240529A: JinShan optical observations
- EP240618a: GSP optical upper limit
- IPN triangulation of GRB 240615A (short)
- X-ray transient EP240618a: Fermi/GBM non-detection
- GRB 240619A: GRBAlpha detection
- EP240618a: Swift/XRT upper limit
- EP240617a: tentative Swift/XRT detection of the afterglow
- GRB 240619A: Swift-XRT probable afterglow detection
- GRB 240619A: Swift ToO observations
- GRB 240619A: CALET Gamma-Ray Burst Monitor detection
- GRB 240619C: NuSTAR automated detection of the GRB
- Fermi GBM Sub-Threshold Detection of GRB 240619C
- GRB 240619A: GOTO candidate optical afterglow
- GRB 240615A: NOT optical observations
- GRB 240619C: AstroSat CZTI detection
- GRB 240615A: possible transient detection from Wendelstein observations
- EP240618a: OHP/T193 MISTRAL i' and Y band upper limits
- EP240618a: BOOTES-6/DPRT optical upper limit
- GRB 240619B: Fermi GBM Final Real-time Localization
- LIGO/Virgo S240615dg: Swift XRT observations, 39 X-ray sources
- GRB240615A: 1.3m DFOT optical upper limit
- GRB 240619A: Fermi GBM Final Real-time Localization
- EP240617a: BOOTES-6/DPRT optical upper limit
- EP240617a is likely a GRB event
- EP240617a: EP-WXT detection of a fast X-ray transient
- EP240618a: EP-WXT detection of a fast X-ray transient and EP-FXT quick follow-up
- LIGO/Virgo/KAGRA S240615ea: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240615dg: Upper limits from Swift/BAT-GUANO
- GRB 240615A: J-band upper limits from WINTER
- GRB 240615A: Fermi GBM Observation
- GRB 240615A: Swift-XRT observations
- GRB 240615A: GECAM detection
- GRB 240615A: FLWO-1.2m optical upper limits
- Konus-Wind detection of GRB 240615A (short/hard)
- GRB 240615A: GOTO optical upper limits
- GRB 240616A: Fermi GBM Final Real-time Localization
- GRB 240615A: Swift ToO observations
- GRB 240615A: Swift/BAT-GUANO arcminute localization of a short burst
- GRB 240615A: Fermi GBM Final Real-time Localization