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"25897 results found.
- Swift GRB 240805A: Global MASTER-Net observations report
- GRB 240805A: Swift-XRT refined Analysis
- GRB 240805B: Swift detection of a burst
- GRB 240805A: Fermi-LAT detection
- GRB 240805A: INTEGRAL spectral analysis
- GRB 240805A: A long GRB detected by INTEGRAL
- GRB 240805A: Swift detection of a burst
- GRB 240730A: Swift-BAT refined analysis
- GRB240730A: BOOTES-5/JGT early optical upper limit
- Swift GRB 240730A: Global MASTER-Net observations report
- GRB 240730A: Swift-XRT refined Analysis
- GRB 240715A: Swift-XRT afterglow detection
- GRB 240730A: KAIT Optical Upper Limit
- GRB 240730A: Swift/UVOT Upper Limits
- GRB 240730A: Enhanced Swift-XRT position
- GRB 240730A: Swift detection of a burst
- GRB 240727A: Swift-BAT refined analysis
- LIGO/Virgo/KAGRA S240615dg: GRAWITA wide-field optical observations
- GRB 240727A: observations of optical counterpart.
- GRB 240727B: Swift-XRT observations
- 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 240713A: optical upper limits from the INAF Asiago Observatory
- 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 240713A: J-band upper limit from WINTER
- GRB 240713A: NOT optical upper limits on three EP/FXT candidates
- GRB 240713A: JinShan optical upper limits
- GRB 240712A: Swift detection of a burst
- EP240708a: SVOM/C-GFT optical upper limit
- 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
- EP240703a: BTA observations
- EP240703c: Kinder optical follow-up and Swift XRT observations
- EP240703a: Liverpool Telescope optical follow-up observations
- EP240703a/GRB 240703A: TRT optical candidate likely not real
- EP240703c: EP-WXT detection of an X-ray transient
- EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
- IPN triangulation of GRB 240627A
- GRB 240619A: Host galaxy redshift from VLT/X-shooter
- 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 240615A: SAI CMO J- band observations
- 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
- GRB240615A: Gemini-North observations of the BAT and XRT positions
- GRB240615A: Gemini-North observations of the BAT and XRT positions
- GRB 240619A: detection of a radio counterpart with AMI-LA
- 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