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').
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To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
23834 results found.
- GRB 241209C: Fermi GBM Observation
- GRB 241209A: Swift-XRT refined Analysis
- LIGO/Virgo/KAGRA S241210fu: Identification of a GW compact binary merger candidate
- EP241208a: Optical upper limit with Kinder observations
- GRB 241209B: SVOM/VT afterglow detection
- LIGO/Virgo/KAGRA S241210cw: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S241210d: Identification of a GW compact binary merger candidate
- GRB 241207B: Fermi GBM Observation
- GRB 241209D: Swift-XRT refined Analysis
- GRB 241209D: Fermi GBM Observation
- GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
- GRB 241209D: COLIBRÍ detection of the afterglow
- GRB 241209A: COLIBRÍ Optical Upper Limit
- GRB 241209C: Swift/BAT-GUANO localization skymap of a burst
- GRB 241209A: GRANDMA/TAROT upper limit
- GRB 241209A: REM optical/NIR observations
- GRB 241209D: Enhanced Swift-XRT position
- GRB 241209D: Swift detection of a burst
- GRB 241209A: Enhanced Swift-XRT position
- GRB 241114B: cubesat Avion detection
- GRB 241209A: VLT optical observations
- GRB 241209A: GOTO optical upper limits
- GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
- EP241208a: EP detection of a fast X-ray transient
- GRB 241209A: Swift detection of a short burst
- 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