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').
18802 results found.
- 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 240225B: Mondy afterglow observations
- IPN triangulation of GRB 240227A (short)
- 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: J-band upper limits from WINTER
- Transient EPW20240219aa: REM optical/NIR upper limits
- GRB 240222A: ATCA radio observations
- GRB 240225B: AstroSat CZTI detection
- Transient EPW20240219aa: Xinglong-2.16m optical upper limit
- 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: upper limit in gamma-ray range from SPI-ACS/INTEGRAL observations
- Transient EPW20240219aa: Liverpool Telescope non-detection and limiting magnitude
- GRB 240222A: GECAM detection of a burst
- 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
- Konus-Wind detection of GRB 240218A
- GRB 240218A: VLT/X-shooter redshift of z = 6.782
- IPN triangulation of GRB 240209A
- GRB 240218A: Enhanced Swift-XRT position
- GRB 240218A: REM detection of a NIR afterglow candidate
- 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 240215A: Swift/BAT-GUANO localization of a burst
- GRB 240213A: Glowbug gamma-ray detection
- GRB 240128A: Further Swift-XRT observations
- GRB 240209A: NOEMA non-detection of AT2024cew / GOTO24pw counterpart candidate
- GRB 240209A: NOT photometry of the AT2024cew / GOTO24pw counterpart candidate
- GRB 240209A: GOTO optical counterpart candidate
- Konus-Wind detection of GRB 240205A (short)
- IPN triangulation of GRB 240205A (short)
- GRB 240205B: PRIME near infrared detection
- GRB 240205A (short): Glowbug gamma-ray detection
- GRB240204A: Swift/UVOT Upper Limits
- GRB 240205B: AstroSat CZTI detection
- Konus-Wind detection of GRB 240125A
- GRB 240205B: VLT/X-shooter redshift
- GRB 240205B: REM detection of the optical/NIR afterglow
- GRB 240204A : OHP/T193/T120 optical afterglow fading detection
- GRB 240205B: Skynet Optical Afterglow Observations
- GRB 240205B: Swift detection of a burst
- 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 240124B
- IPN triangulation of GRB 240124B
- GRB 240201A: AstroSat CZTI detection
- IPN triangulation of GRB 240125B (short)
- IPN triangulation of GRB 240125A (short)
- GRB 240128A: Glowbug gamma-ray detection
- GRB 240122A: ATCA detection of radio counterpart
- GRB240122A: PRIME near infrared detection
- GRB 240123A: Glowbug gamma-ray detection
- GRB 240125A (short): Glowbug gamma-ray detection
- IPN triangulation of GRB 240123C (short)
- GRB 240123A: further SAO RAS optical observations
- 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
- GRB 240123A: Swift detection of a burst with a possible optical counterpart
- GRB 240122A: Swift-XRT afterglow detection
- GRB 240122A: LT non-detection of GOTO candidate counterpart confirms fading
- 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
- GRB 240117A: AstroSat CZTI detection
- GRB 240118A: AbAO optical upper limit
- GRB 240117A: Glowbug gamma-ray detection
- GRB 240118A: Fermi GBM Observation
- IPN triangulation of GRB 240112A (long)
- GRB 240112D: Glowbug gamma-ray detection
- GRB 240112C: Glowbug gamma-ray detection
- GRB 240112C: VZLUSAT-2 detection
- GRB 240112C: Swift/UVOT Detection
- GRB 240112C: Swift-XRT refined Analysis
- GRB 240112C: SAO RAS optical observations
- GRB 240112C: Swift detection of a burst with an optical counterpart
- GRB 240112A: GECAM detection of a burst