GCN Circulars
GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"27827 results found.
- GRB 250225B: VLT/FORS2 candidate optical afterglow
- GRB 250225B: SVOM/GRM observation of a long burst
- GRB 250226A: GECAM-B detection
- GRB 250221A: EP-FXT detection of the X-ray afterglow
- EP250226a/GRB 250226A: GSP detects optical counterpart
- EP250226a/GRB 250226A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
- EP250226a / GRB 250226A: VLT/X-shooter redshift of z = 3.315
- LIGO/Virgo S250223dk: Swift XRT observations, 7 X-ray sources
- Swift GRB 250225B: Global MASTER-Net observations report
- EP250226a/GRB 250226A: EP-WXT detection and FXT follow-up observation of an X-ray transient
- GRB 250226A: Fermi GBM Final Real-time Localization
- EP250225a: GSP optical upper limit
- EP250225a: Einstein Probe detected of a fast X-ray transient
- GRB 250225B: Swift detection of a burst
- GRB 250221A: Swift-BAT refined analysis
- LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: DECam GW-MMADS candidates
- GRB 250225A: Fermi GBM Final Real-time Localization
- LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: AstroSat CZTI non-detection and upper limits
- LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Magellan upper limits.
- GRB 250207a: ATCA Radio Upper Limits
- LIGO/Virgo/KAGRA S250223dk: DECam DESGW Candidates
- LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Upper limits from Fermi-GBM Observations
- GRB 250119B: VZLUSAT-2 detection
- GRB 250223C: Fermi GBM Final Real-time Localization
- GOTO observations of LVK S250223dk/Swift-BAT RAVEN alert
- GRB 250202B: VZLUSAT-2 detection
- GRB 250219A: EP-FXT afterglow detection
- EP250223a: COLIBRÍ/DDRAGO Detection of the Optical Counterpart and Slow Fading
- GRB 250210A: VZLUSAT-2 detection
- GRB 250206A: VZLUSAT-2 detection
- EP250223a: REM NIR upper limit
- EP250223a: TRT optical afterglow observation
- EP250223a: refined analysis of the EP-WXT and FXT observations
- GRB 250221A: TNOT detection of the optical counterpart
- EP250223a: SVOM/VT optical observation
- LIGO/Virgo/KAGRA S250223dk: DDOTI Upper Limits on the Optical Counterpart
- LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO trigger with ID 762004910: Identification of a GW compact binary merger candidate possibly associated with a sub-threshold Swift/BAT-GUANO trigger
- EP250223a: OASDG optical observations
- EP250223a: LCO detection of the afterglow
- EP250223a: early optical detection by BOOTES-4
- EP250223a: NOT redshift z = 2.756
- EP250223a: Swift/XRT localization
- GRB 250223B: Fermi GBM Final Localization
- GRB 250221A: VLA radio detection
- GRB 250223A: Fermi GBM Final Real-time Localization
- EP250223a: Einstein Probe detection of an X-ray transient
- GRB 250221A: continued Assy optical observations, brightening afterglow confirmation
- GRB 250221A: continued Mondy optical observations, brightening afterglow
- GRB 250221A: Optical counterpart detection by LCO.
- GRB 250221A: Mondy optical observations
- Konus-Wind detection of GRB 250221A
- GRB 250221A: Assy optical observations
- EP250220a: EP-FXT follow-up observations
- GRB 250221A: GRANDMA/TAROT Detection
- GRB 250221A: Swift-XRT refined Analysis
- GRB 250221A: NOT optical observations
- GRB 250221A: 1.6m Mephisto optical detection
- GRB 250221A: AKO Optical Upper Limit
- GRB 250221A: Swift/UVOT Detection
- GRB 250219A: GRANDMA/Kilonova-Catcher upper limits
- GRB 250221A: REM optical/NIR afterglow detection
- GRB 250221A: Enhanced Swift-XRT position
- EP250220a: Liverpool Telescope optical upper limits
- EP250220a: Optical upper limit with Kinder observations
- SVOM trigger sb25022102 is not an astrophysical event
- SVOM/sb25022102: SVOM detection of an X-ray transient
- GRB 250221A: COLIBRÍ/DDRAGO Confirmation of a Bright Optical Counterpart
- GRB 250221A: Swift detection of a burst with an optical counterpart
- Swift GRB250221.15: Global MASTER-Net OT detection
- Swift GRB250221.15: Global MASTER-Net observations report
- EP250220a: Xinglong optical upper limit
- GRB 250220B: Fermi GBM Final Real-time Localization
- GRB 250220A: Fermi GBM Final Real-time Localization
- EP250220a: EP-WXT detection of a fast X-ray transient
- Konus-Wind detection of GRB 250217C (short)
- GRB 250219A: Swift/UVOT Upper Limits
- GRB 250219A: COLIBRÍ/DDRAGO Detection of the Optical Counterpart
- GRB 250219A: 1.6m Mephisto optical upper limits
- GRB 250219A: SVOM/VT optical counterpart
- GRB 250219A: Swift-XRT observations
- GRB 250219A: Swift ToO observations
- GRB 250219A: SVOM detection of a burst
- Konus-Wind detection of GRB 250215A / EP250215a
- GRB 250217C: Swift-XRT observations
- SVOM/sb25021804: QSO variability in Liverpool Telescope observations
- GRB 250217C: COLIBRÍ/DDRAGO Upper Limits on the Optical Counterpart
- GRB 250217C: Tiled Swift observations
- IPN triangulation of GRB 250217C (short)
- Transient SVOM/sb25021804: COLIBRÍ/DDRAGO Optical Upper Limits on the Optical Counterpart
- SVOM/sb25021804: SVOM detection of a long X-ray transient
- GRB 250213A: Swift-XRT observations
- GRB 250216A: AstroSat CZTI detection
- GRB 250217C: AstroSat CZTI detection of a short burst
- GRB 250217C: Fermi GBM Final Real-time Localization
- GRANDMA/OPD observations of GRB250215A
- GRB 250217B: Fermi GBM Final Real-time Localization
- GRB 250217A: Fermi GBM Final Real-time Localization
- GRB 250215A / EP250215a: LCO detection of the afterglow
- GRB 250216A: Fermi GBM Final Real-time Localization
- GRB 250215A: Swift/UVOT Upper Limits