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"19875 results found.
- GRB 240727A: Swift/UVOT detection
- GRB 240727A: NOT optical observation
- GRB 240727A: JinShan optical upper limits
- GRB 240727A Bassano Bresciano Observatory upper limit
- GRB 240727A: Swift-XRT refined Analysis
- GRB 240727A: Enhanced Swift-XRT position
- GRB 240727B: Fermi GBM Observation
- Swift GRB240727.16: Global MASTER-Net observations report
- GRB 240727B: Swift ToO observations
- GRB 240727B: Swift/BAT-GUANO arcminute localization of a long burst
- GRB240727A: Skynet Optical Afterglow Observations
- GRB 240727A: TRT optical afterglow detection
- GRB 240727A: KAIT Optical Afterglow Candidate
- GRB 240727A: Swift detection of a burst
- Swift Trigger 1244778 is not a GRB
- Swift GRB240725.11: Global MASTER-Net observations report
- GRB 240720A: Swift-BAT refined analysis
- LIGO/Virgo/KAGRA S240716b: Upper limits from Swift/BAT-GUANO
- LIGO/Virgo/KAGRA S240703ad: Upper limits from Swift/BAT-GUANO
- GRB 240720A: AstroSat CZTI detection
- GRB 240720A: Fermi GBM observation
- GRB 240720A: Swift detection of a burst
- Swift GRB240720.02: Global MASTER-Net observations report
- GRB 240718A: Fermi-LAT Detection
- GRB 240712A: Swift-BAT refined analysis
- GRB 240715A: Swift/UVOT observations of the XRT sources.
- GRB 240715A: Swift-XRT observations
- GRB240713A: Swift/UVOT Upper LImits
- EP240708a: X-ray follow-up observations with Swift/XRT
- GRB 240713A: Swift-XRT observations
- GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
- GRB 240712A: Swift-XRT refined Analysis
- GRB 240715A: Swift ToO observations
- GRB 240712A ATCA radio observations
- IPN triangulation of GRB 240715A (short)
- GW s240422ed: Swift UVOT follow-up
- GRB 240712A: Swift/UVOT Upper Limits
- The EP-WXT source triggered on July 14th is likely a flaring star
- GRB 240713A: Tiled Swift observations
- GRB 240712A: Swift detection of a burst
- 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
- IPN triangulation of GRB 240628B (short)
- EP240703a and EP240703b: Swift/XRT upper limits
- EP240703c: Kinder optical follow-up and Swift XRT observations
- EP240703c: EP-WXT detection of an X-ray transient
- IPN triangulation of GRB 240627A
- EP240703b: EP-WXT detection of a fast X-ray transient
- EP240702a: Swift/XRT upper limit
- EP240703a: EP-WXT detection of a fast X-ray transient
- EP240702a: EP-WXT detection of a fast X-ray transient
- LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
- IPN triangulation of GRB 240619C
- GRB 240624A: Swift-BAT refined analysis
- Konus-Wind detection of GRB 240619A
- 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 240624A: Swift detection of a burst
- GRB 240529A: JinShan optical observations
- IPN triangulation of GRB 240615A (short)
- 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 240615A: NOT optical observations
- GRB 240615A: possible transient detection from Wendelstein observations
- LIGO/Virgo S240615dg: Swift XRT observations, 39 X-ray sources
- GRB240615A: 1.3m DFOT optical upper limit
- 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 240615A: Swift ToO observations
- GRB 240615A: Swift/BAT-GUANO arcminute localization of a short burst
- EXO 0748-676: Swift-BAT refined analysis
- GRB240529A: 3.6m TNG NIR detection 8d after the burst
- GRB 240529A: LBT optical detection and late temporal decay
- GRB 240529A : MITSuME Akeno optical afterglow detection
- Trigger 1236151: Swift detection of EXO 0748-676
- IPN triangulation of GRB 240607A
- Konus-Wind detection of GRB 240606B
- GRB 240606B: Fermi GBM Observation
- Swift Trigger 1235109: consistent with noise and not astrophysical
- GRB 240606B: GECAM-B detection a long burst
- GRB 240606B: Swift-XRT afterglow detection
- Swift GRB240606.15: Global MASTER-Net observations report
- GRB 240606B: Swift ToO observations
- GRB 240606B: Swift/BAT-GUANO arcminute localization of a burst
- Swift Trigger 1235109: a possible GRB 240606A
- IPN triangulation of GRB 240531A (short)
- Swift Trigger 1232755: likely consistent with noise and not astrophysical