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').
17519 results found.
- GRB 240819A: TRT optical upper limits on the Swift/XRT and EP/FXT sources
- GRB 240819A: Swift ToO observations
- GRB GRB 240809A: Osservatorio Astronomico "Nastro Verde" optical observations: detection of an optical counterpart
- GRB 240805B: Osservatorio Astronomico Nastro Verde upper limit
- EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
- Konus-Wind detection of GRB 240811A
- GRB 240811A: Swift-BAT refined analysis
- GRB 240809A: Swift-BAT refined analysis
- GRB 240811A: Bassano Bresciano Observatory upper limit
- GRB 240811A: Swift-XRT refined Analysis
- GRB 240811A: Swift/UVOT Upper Limits
- GRB 240811A: LCOGT Optical Upper Limit
- GRB 240811A: Enhanced Swift-XRT position
- Konus-Wind detection of GRB 240809A
- Swift GRB 240811A: Global MASTER-Net observations report
- GRB 240811A: Swift detection of a burst
- GRB 240809A: Bassano Bresciano Observatory optical observations
- GRB 240809A: KAIT 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
- Swift GRB 240809A: Global MASTER-Net observations report
- GRB 240809A: JinShan optical observations
- GRB 240809A: Enhanced Swift-XRT position
- GRB 240809A: Skynet & Photon Ranch Optical Afterglow Observations
- GRB 240809A: SVOM/GRM observation
- GRB 240809A: Swift detection of a burst with a bright optical counterpart
- GRB 240805A: ATCA Radio Upper Limits
- GRB 240805B: GIT optical upper limit
- GRB 240805B: Swift-BAT refined analysis
- GRB 240805A: Swift-BAT refined analysis
- Konus-Wind detection of GRB 240805A
- GRB 240805B Bassano Bresciano Observatory upper limit
- GRB240805A: Fermi GBM Observation
- GRB 240805B: JinShan optical afterglow detection
- GRB 240805B: AbAO, CrAO, and Terskol optical upper limits
- GRB 240805B: Swift-XRT refined Analysis
- GRB 240805B: Swift/UVOT Upper Limits
- GRB 240805A: Swift/UVOT Upper Limits
- GRB 240805A: SVOM/GRM observation
- GRB 240805B: Enhanced Swift-XRT position
- GRB 240805B: LCOGT Optical Upper Limits
- Swift GRB 240805B: Global MASTER-Net observations report
- GRB 240805B: JinShan optical upper limits
- 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 240712A ATCA radio observations
- IPN triangulation of GRB 240715A (short)