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').
17298 results found.
- GRB 240229A: DDOTI Upper Limits on the Afterglow
- GRB 240218A: NOEMA upper limit
- GRB 240225B: further SAO RAS optical observations
- Konus-Wind detection of GRB 240225B (long)
- GRB 240225B: VLT/X-shooter redshift
- GRB 240225B : MITSuME Akeno optical afterglow candidate detection
- GRB 240225B: 3.6m DOT observation
- GRB 240225B: WINTER near-IR observations and upper limits
- GRB 240225B: SAO RAS optical observations
- GRB 240226A: GRBAlpha detection
- GRB 240225B: Mondy afterglow observations
- GRB 240218A: CMO SAI NIR upper limit
- GRB 240225B: Nanshan/HMT optical afterglow detection
- GRB 240225B: Swift-XRT observations
- Transient EPW20240219aa: Kp-band imaging observations with NIRES
- Transient EPW20240219aa: REM optical/NIR upper limits
- GRB 240225C: GRBAlpha detection
- GRB 240225B: AstroSat CZTI detection
- Transient EPW20240219aa: Xinglong-2.16m optical upper limit
- GRB 240222A: GRBAlpha detection
- Transient EPW20240219aa: GECKO: LOAO Optical Upper Limits
- Transient EPW20240219aa: 7DT Optical Upper Limits
- VLA X-band observation of EPW20240219aa
- Transient EPW20240219aa: Mondy optical observations
- Transient EPW20240219aa: Liverpool Telescope non-detection and limiting magnitude
- GRB 240222A: Swift-XRT refined Analysis
- GRB 240222A: Swift/UVOT Upper Limits
- GRB 240222A: REM optical and NIR early-time observations
- GRB 240222A: Swift detection of a burst
- GRB 240218A: MeerLICHT upper limits
- GRB 240216A: Glowbug gamma-ray detection
- GRB 240218A: LBT H-band detection
- GRB 240218A: VLT/X-shooter redshift of z = 6.782
- GRB 240216A: GRBAlpha detection
- GRB 240215B: GRBAlpha detection
- GRB 240218A: Enhanced Swift-XRT position
- GRB 240218A: REM detection of a NIR afterglow candidate
- GRB 240213A: GRBAlpha detection
- GRB 240218A : r-band upper limit from Observatoire de Haute-Provence
- GRB240218A: VLT/X-shooter upper limits
- GRB 240218A: Swift detection of a burst
- GRB 240213A: Glowbug gamma-ray detection
- GRB 240128A: Further Swift-XRT observations
- GRB 240209A: NOT photometry of the AT2024cew / GOTO24pw counterpart candidate
- Konus-Wind detection of GRB 240204A
- IPN triangulation of GRB 240205A (short)
- Fermi-LAT gamma-ray observations of IceCube-240204A
- GRB 240205B: PRIME near infrared detection
- GRB 240205A (short): Glowbug gamma-ray detection
- GRB240204A: Swift/UVOT Upper Limits
- Konus-Wind detection of GRB 240205B (long / very soft)
- Konus-Wind detection of GRB 240125A
- GRB 240205B: VLT/X-shooter redshift
- GRB 240205B: CALET Gamma-Ray Burst Monitor detection
- GRB 240205B: REM detection of the optical/NIR afterglow
- GRB 240204A: AstroSat CZTI detection
- GRB 240204A : OHP/T193/T120 optical afterglow fading detection
- GRB 240205B: Skynet Optical Afterglow Observations
- GRB 240205B: Fermi GBM Final Real-time Localization
- GRB 240205A: Fermi GBM Final Real-time Localization
- GRB 240204a: Liverpool Telescope optical afterglow detection
- GRB 240204A: Osservatorio Astronomico Nastro Verde upper limit
- GRB 240204A: optical afterglow detection with LCOGT 1m telescopes at Sutherland and Teide Observatories
- GRB 240204A: Montarrenti Observatory optical observations
- GRB 240204A: Enhanced Swift-XRT position
- GRB 240204A: Mondy optical afterglow candidate
- GRB 240204A: Swift detection of a burst
- Konus-Wind detection of GRB 240123C
- IPN triangulation of GRB 240124B
- GRB 240201A: AstroSat CZTI detection
- GRB 240128A: Glowbug gamma-ray detection
- GRB 240128A: GRBAlpha detection
- GRB 240125A: GRBAlpha detection
- GRB 240123C: GRBAlpha detection
- GRB 240125A: AstroSat CZTI detection of a short burst
- GRB 240124B: AstroSat CZTI detection
- GRB240122A: PRIME near infrared detection
- GRB 240123A: Glowbug gamma-ray detection
- GRB 240125A (short): Glowbug gamma-ray detection
- GRB 240123A: GRBAlpha detection
- IPN triangulation of GRB 240123C (short)
- Fermi-LAT gamma-ray observations of IceCube-240123A
- GRB 240123A: further SAO RAS optical observations
- GRB 240123A: Swift-BAT refined analysis
- GRB 240123A: SAO RAS optical observations
- GRB 240123A : MITSuME Akeno optical afterglow candidate detection
- GRB 240123A: Enhanced Swift-XRT position
- GRB 240122A: Swift/UVOT Upper Limits
- GRB 240118A: Swift/UVOT Upper Limits
- GRB 240122B: Glowbug gamma-ray detection
- GRB 240123A: Mondy optical afterglow observations
- Konus-Wind detection of GRB 240112A
- GRB 240123A: Swift detection of a burst with a possible optical counterpart
- GRB 240122A: Swift-XRT afterglow detection
- GRB 240122A: GOTO optical counterpart candidate
- Konus-Wind detection of GRB 240119A (short/hard)
- IPN triangulation of GRB 240119A (short)
- GRB 240118A: Mondy optical observations
- GRB 240118A: Swift-XRT afterglow detection
- IceCube-240105A: Detection of NIR flare of PKS 0446+11 with WINTER