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"
24608 results found.
- Fermi GRB 241207B: Global MASTER-Net observations report
- GRB 241207B: Swift/BAT-GUANO localization skymap of a short burst
- GRB 241206A: DDOTI Upper Limit on the Afterglow
- AT2024adec: X-ray Upper Limits from EP-FXT Observation
- GRB 241207C: MAXI/GSC detection
- EP241206a: EP detection of a fast X-ray transient
- GRB 241206A: Fermi GBM observation
- GRB 241206A: Swift/BAT-GUANO localization skymap of a burst
- EP241201a: 1.6m Mephisto Optical Upper Limits
- GRB 241204A: COLIBRÍ Optical Upper Limit
- EP241202b: KAIT optical upper limit
- LIGO/Virgo/KAGRA S241125n: gamma-ray upper limits from joint observations by the LST-1 and MAGIC telescopes
- GRB 241204A: DDOTI Upper Limits on the Afterglow
- GRB 241130A: CALET Gamma-Ray Burst Monitor detection
- GRB 241128A : RAPAS follow-up observations
- EP241202b: Upper limits from Fermi-GBM Observations
- IceCube-241127A: No transient candidates from the Zwicky Transient Facility
- EP241202b: Kinder optical counterpart candidate
- Fermi-GBM Sub-Threshold Detection of GRB 241128A
- GRB 241113B : RAPAS follow-up observation
- Konus-Wind detection of GRB 241130A
- EP241201a: BOOTES-5 optical upper limit
- EP241202b: EP detection of a fast X-ray transient
- EP241201a: NOT optical observations
- IPN triangulation of GRB 241130A
- GRB 241130A: EIRSAT-1 GMOD Detection
- GRB 241128A: Swift/UVOT Upper Limits
- GRB 241130A: Fermi GBM Detection
- IceCube-241127A: Upper limits from a search for additional neutrino events in IceCube
- GRB 241129A: Swift/BAT-GUANO localization skymap of a burst
- EP241201a: Kinder optical counterpart candidate
- LIGO/Virgo/KAGRA S241102br: GRAWITA wide-field optical observations
- LIGO/Virgo/KAGRA S241201ac: Updated Sky localization
- GRB 241201A: BALROG localization (Fermi Trigger 754757764 / GRB 241201622)
- EP241126a: 1.6m Mephisto Optical Upper Limits
- GRB 241201A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S241201ac: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S241130be: Updated Sky localization
- Fermi trigger No 754701230: Global MASTER-Net observations report
- LIGO/Virgo/KAGRA S241130n: Updated Sky localization
- LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
- GRB 241128A: AbAO optical upper limit
- LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
- LIGO/Virgo/KAGRA S241130be: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S241129aa: Updated Sky localization
- LIGO/Virgo/KAGRA S241130n: Identification of a GW compact binary merger candidate
- GRB 241128A: Swift-BAT refined analysis
- GRB 241127A: Swift-BAT refined analysis
- GRB 241127A: PRIME near-infrared detection
- GRB 241128A: Mondy optical observations
- GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
- Swift-XRT observations of IceCube -241127A
- Fermi-LAT gamma-ray observations of IceCube-241127A
- LIGO/Virgo/KAGRA S241129aa: Identification of a GW compact binary merger candidate
- GRB 241128A: Swift-XRT refined Analysis
- GRB 241128A: Enhanced Swift-XRT position
- GRB 241128A: NOT optical observations
- GRB 241128A: LCO optical detection
- LIGO/Virgo S241127aj: GRANDMA/FRAM-CTA-N Observations
- GRB 241128A: Swift-XRT afterglow detection
- GRB 241128A: Swift detection of a burst
- GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
- GRB 241127A: Swift/UVOT Detection
- GRB 241127A: Swift-XRT refined Analysis
- GRB 241127A: Enhanced Swift-XRT position
- LIGO/Virgo/KAGRA S241127aj: Updated Sky localization
- GRB 241127A: LCOGT (40-cm) optical counterpart detection
- Swift GRB241127.91: Global MASTER-Net OT detection
- EP241126a: WFST Observations
- LIGO/Virgo/KAGRA S241125n: Update on Coincidence False Alarm Method
- GRB 241127A: Swift detection of a burst with an optical counterpart
- Swift GRB241127.91: Global MASTER-Net OT detection
- LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
- LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
- LIGO/Virgo/KAGRA S241127aj: NED Galaxies in the Localization Volume
- EP241126a: Optical Upper limits with Kinder observations
- IPN triangulation of GRB 241114B
- EP trigger ID 01709122294: 1.6m Mephisto multi-band optical observations
- EP241126a: GSP detects optical counterpart
- EP241126a: TRT optical counterpart detection
- LIGO/Virgo/KAGRA S241127aj: Identification of a GW compact binary merger candidate
- EP241126a: EP detection of a fast X-ray transient
- LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on Optical Counterparts to Two of the Swift/XRT Sources
- LIGO/Virgo/KAGRA S241125n: SAGUARO follow-up observations with the MMT
- LIGO/Virgo/KAGRA S241125n: DDOTI Optical Upper Limits
- LIGO/Virgo/KAGRA S241125n: Gaoyazi/GOT optical observations
- GECAM detection of a short burst from SGR 1830
- LIGO/VIRGO/KAGRA S241125n: GROWTH-India telescope optical observations
- LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
- LIGO/Virgo/KAGRA S241125n: HCT upper limit
- LIGO/Virgo/KAGRA S241125n: Upper limits from Konus-Wind observations
- GRB 241026A: radio detection with the VLA
- EP241125a: Optical upper limit with Kinder observations
- EP241125a: EP detection of an X-ray transient
- LIGO/Virgo/KAGRA S241125n: COLIBRÍ Upper Limits on a Optical Counterpart at the BAT Position
- LIGO/Virgo/KAGRA S241125n: Upper limits from Fermi-GBM Observations
- LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event
- LIGO/Virgo/KAGRA S241125n: Kinder optical upper limit in the BAT error region
- LIGO/Virgo/KAGRA S241125n: Updated Sky localization
- LIGO/Virgo/KAGRA S241125n: Updated Coincidence with External Event