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').
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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"7445 results found.
- LIGO/Virgo/KAGRA S230627c: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230624av: Updated Sky localization
- LIGO/Virgo/KAGRA S230624av: Identification of a GW compact binary merger candidate
- GRB 230623A: Tiled Swift observations
- GRB 230623A: Tiled Swift observations
- LIGO/Virgo/KAGRA S230615az: LBT spectroscopic classification of GOTO23hn
- LIGO/Virgo/KAGRA S230622ba: Retraction of GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230615az: LBT spectroscopic redshift of the host galaxy of GOTO23hn
- Fermi GBM-230619: AstroSat CZTI non-detection and upper limits for the sub-threshold candidate
- GRB 230622A: Swift detection of a burst
- Fermi GBM-230619: A soft subthreshold candidate potentially associated with a subthreshold LIGO/Virgo compact binary merger candidate
- LIGO/Virgo/KAGRA S230619bg: one counterpart neutrino candidate from IceCube neutrino searches
- LIGO/Virgo/KAGRA S230615az: Wendelstein observations of DESI galaxies and GIT candidates
- ZTF23aaoohpy/AT2023lcr: GROWTH-India Telescope follow-up observations
- ZTF23aaoohpy/AT2023lcr: GOTO early optical observations and constraint
- ZTF23aaoohpy/AT2023lcr: Zwicky Transient Facility discovery of a fast fading red transient
- GRB 230618A: Swift detection of a burst
- GRB 230616A: Swift ToO observations
- LIGO/Virgo/KAGRA S230615az: T80S Search and Candidate Counterpart Identification
- LIGO/Virgo/KAGRA S230615az: Xinglong-2.16m photometric observations of GIT candidates
- LIGO/Virgo/KAGRA S230529ay: Upper limits from a two-week IceCube neutrino search
- LIGO/Virgo/KAGRA S230615az: GOTO candidate counterparts
- LIGO/Virgo/KAGRA S230608as: Updated Sky localization
- LIGO/Virgo/KAGRA S230606d: Updated Sky localization
- LIGO/Virgo/KAGRA S230609u: Updated Sky localization
- LIGO/Virgo/KAGRA S230609u: Identification of a GW compact binary merger candidate
- ZTF23aamxeqf/AT2023jxk: 1.3m DFOT Optical upper limit
- LIGO/Virgo/KAGRA S230608as: Identification of a GW compact binary merger candidate
- ZTF and GIT Observations of the Candidate Optical Afterglow AT2023jxk
- LIGO/Virgo/KAGRA S230606d: Identification of a GW compact binary merger candidate
- Fermi-LAT gamma-ray observations of IceCube-230603A
- LIGO/Virgo/KAGRA S230605o: Updated Sky localization
- LIGO/Virgo/KAGRA S230601bf: Updated Sky localization
- LIGO/Virgo/KAGRA S230605o: Identification of a GW compact binary merger candidate
- IceCube-230603A - IceCube observation of a high-energy neutrino candidate track-like event
- LIGO/Virgo/KAGRA S230518h: Upper limits from a two-week IceCube neutrino search
- LIGO/Virgo/KAGRA S230601bf: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230529ay: Upper limits from CALET observations.
- LIGO/Virgo/KAGRA S230529ay: AstroSat CZTI non-detection and upper limits
- LIGO/Virgo/KAGRA S230529ay: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/KAGRA S230529ay: Upper limits from Fermi-GBM Observations
- LIGO/Virgo/KAGRA S230529ay: Updated Sky localization and EM Bright Classification
- LIGO/Virgo/KAGRA S230529ay: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo/KAGRA S230529ay: Identification of a GW compact binary merger candidate
- LIGO/Virgo/KAGRA S230518h: Updated Sky localization
- LIGO/Virgo/KAGRA S230520ae: Updated Sky localization
- LIGO/Virgo/KAGRA S230518h: Upper limits from Glowbug gamma-ray observations
- LIGO/Virgo/KAGRA S230518h: TESS observations of the localization region
- LIGO/Virgo/KAGRA S230524x: Retraction of GW compact binary merger candidate
- IceCube-230524A - IceCube observation of a high-energy neutrino candidate track-like event
- LIGO/Virgo/KAGRA S230522n: Upper limits from IceCube neutrino search
- LIGO/Virgo/KAGRA S230522a: 2 counterpart neutrino candidates from IceCube neutrino searches
- LIGO/Virgo/KAGRA S230521k: Zwicky Transient Facility observations
- IPN triangulation of GRB 230518A (short)
- LIGO/Virgo/KAGRA S230520ae: Identification of a GW compact binary merger candidate: End-to-End Test
- LIGO/Virgo/KAGRA S230520ae: Upper limits from IceCube neutrino search
- LIGO/Virgo/KAGRA S230518h: ATCA follow-up of candidate counterparts
- LIGO/Virgo/KAGRA S230518h: ATLAS observations of the skymap
- LIGO/Virgo/KAGRA S230518h: Swope Search and Candidate Counterpart Identification
- LIGO/Virgo/KAGRA S230518h: Coverage and upper limits from MAXI/GSC observations
- LIGO/Virgo/Kagra S230518h: NED Galaxies in the Localization Volume
- LIGO/Virgo/KAGRA S230518h: AstroSat CZTI non-detection and upper limits
- LIGO/Virgo/KAGRA S230518h: Upper limits from Fermi-GBM Observations
- LIGO/Virgo/KAGRA S230518h: Updated Sky localization and EM Bright Classification
- LIGO/Virgo S230518h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S230518h: Upper limits from IceCube neutrino search
- LIGO/Virgo/KAGRA S230518h: Identification of a GW compact binary merger candidate
- GRB 230513A: Zwicky Transient Facility continuous observations of a Fermi Short GRB (Trigger 705709044)
- IPN triangulation of GRB 230512A
- GRB 230513A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
- GRB 230512A: Nanshan/NEXT non-detection of GRB afterglow candidate
- GRB 230512A: Zwicky Transient Facility non-detection of GRB afterglow candidate
- GRB 230512A: Liverpool Telescope observations
- GRB 230512A: GIT non detection of afterglow candidate
- GRB 230512A: Kitab possible afterglow candidate
- GRB 230512A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705565670)
- GRB 230430A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 704533643)
- GRB 230511D: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705537623)
- GRB 230512A: Tiled Swift observations
- GRB 230510A: LCOGT Optical Upper Limit
- IceCube-230511A: IceCube observation of a high-energy neutrino candidate
- GRB 230510A: Swift detection of a burst
- GRB 230506C: Candidate afterglow observation by D50
- GRB 230506C: TSHAO possible afterglow candidate
- GRB 230506B: Swift/UVOT Detection
- IceCube-230506A: IceCube observation of a high-energy neutrino candidate
- GRB 230430A: A short GRB from a neutron star merger
- GRB 230427A: Swift detection of a burst with an optical counterpart
- Swift Trigger 1165354 is probably not a GRB
- GRB 230420A: Swift detection of a burst
- IceCube-230416A: IceCube observation of a high-energy neutrino candidate
- GRB 230414B (correction GRB name in the GCN 33615): Mondy optical afterglow candidate
- GRB 230414A: Mondy optical afterglow candidate
- GRB 230414B: Swift detection of a burst
- GRB 230409B: Swift detection of a burst
- GRB 230307A: JWST NIRSpec observations, possible higher redshift
- GRB 230307A: further analysis of the Konus-Wind detection and rest-frame energetics
- GRB 230307A: good match with kilonova models
- GRB 230307A: short mininum variability timescale compatible with a merger origin
- GRB 230405B: Swift detection of a burst