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').
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"
6098 results found.
- LIGO/Virgo S190923y: optical spectrum of MASTER detected transient
- LIGO/Virgo S190930t: Transient found in Swift/UVOT counterpart search
- LIGO/Virgo S190930t: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190930s: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190930t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190930s: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 190926A: Swift-XRT refined Analysis
- LIGO/Virgo S190924h: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190924h: no counterpart candidates in AGILE-GRID observations
- Fermi-LAT Gamma-ray Observations of IceCube-190922B
- LIGO/Virgo S190924h: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- LIGO/Virgo S190923y: No counterpart candidates in Fermi-LAT observations
- Fermi-LAT Gamma-ray Observations of IceCube-190922A
- IceCube-190922B - HAWC follow-up
- LIGO/Virgo S190923y: INTEGRAL IBIS coded-masked imaging observations of part of the localization area and further all-sky upper limits
- LIGO/Virgo S190923y: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- IceCube-190922A - HAWC follow-up
- IceCube-190922A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 190919B: Swift-XRT observations
- GRB 190919B: GROND detection of the NIR afterglow
- HAWC-190916A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- Alert from the HAWC Burst Monitor HAWC-190917A
- LIGO/Virgo S190915ak: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190915ak: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190910h: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190910d: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190910h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190910d: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 190823A: Swift-XRT afterglow detection
- GRB 190903A: Fermi GBM detection
- Chandra observations of GW170817 ~740-743 days since merger
- LIGO/Virgo S190901ap: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190901ap: No counterpart candidates in INTEGRAL SPI-ACS,prompt observation
- GRB 190829A: TNG imaging of the NIR afterglow
- GRB 190829A: Fermi GBM detection
- GRB 190829A: Fermi-LAT Upper Limits
- GRB 190829A: GROND detection of the Optical/NIR Afterglow
- GRB 190829A: Swift-XRT refined Analysis
- GRB 190828B: Swift-XRT refined Analysis
- GRB 190828A: Swift-XRT observations
- LIGO/Virgo S190828l: No counterpart candidates in Fermi-LAT observations
- GRB 190828B: Fermi GBM observation
- LIGO/Virgo S190828j: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190814bv: no variation of DESGW candidates AT 2019onj and AT 2019okr from ENGRAVE VLT/HAWK-I observations, and archival detection
- LIGO/Virgo S190828l: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190828j: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190814bv: SALT optical spectrum of candidate DG19aqbkc
- LIGO/Virgo S190814bv: LCO Photometry of DG19wxnjc/AT2019npv
- GRB 190823A: Swift-XRT observations
- GRB 190816A: Swift-XRT afterglow detection
- GRB 190824A: Swift-XRT refined Analysis
- GRB 190824A: Fermi GBM observation
- LIGO/Virgo S190814bv: GROND follow-up observations of AT2019npv
- LIGO/Virgo S190814bv: ENGRAVE VLT/HAWK-I observations and archival detection of the CFHT candidate
- GRB 190821A: Swift-XRT refined Analysis
- GRB 190821A: Fermi GBM observation
- Fermi GBM-190816: No counterpart candidates in Fermi-LAT observations
- Fermi-LAT Gamma-ray Observations of IceCube-190819A
- IceCube-190819A - HAWC follow-up
- Fermi GBM-190816: Location-dependent upper limits from INTEGRAL/SPI-ACS prompt observation
- IceCube-190819A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190814bv: No strong counterpart candidates in Swift/XRT observations
- GRB 190816A: Swift-XRT observations
- LIGO/Virgo S190814bv: Fermi-LAT search for a high-energy gamma-ray counterpart
- LIGO/Virgo S190814bv: GRAWITA TNG infrared imaging of desgw-190814e, DG19sevhc and selected galaxies
- LIGO/Virgo S190814bv: Konus-Wind observations
- LIGO/Virgo S190814bv: GRAWITA TNG infrared imaging of selected galaxies
- LIGO/Virgo S190814bv: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- HAWC-190806A: upper limits from INTEGRAL SPI-ACS and IBIS prompt observation
- HAWC-190806A: Swift-XRT observations
- HAWC Burst Alert 1008846_957: Konus-Wind observations
- GRB 190804B: Swift-XRT afterglow detection
- Alert from the HAWC Burst Monitor
- GRB 190805B: Swift-XRT observations
- GRB 190805B: Fermi GBM detection
- GRB 190804B: Swift-XRT observations
- GRB 190731A: Swift-XRT afterglow detection
- GRB 190731A: Fermi GBM detection
- GRB190731A: Fermi-LAT detection
- Fermi-LAT Gamma-ray Observations of IceCube-190730A
- IceCube-190730A - HAWC follow-up
- IceCube 190730A: one weakly associated counterpart candidates in INTEGRAL SPI-ACS, and IBIS prompt observation
- LIGO/Virgo S190728q: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190728q: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 190727B: Fermi-LAT detection
- GRB 190727B: Fermi GBM observations
- LIGO/Virgo S190727h: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S190727h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- LIGO/Virgo S190718y: Swift XRT observations, 45 X-ray sources
- LIGO/Virgo S190720a: No counterpart candidates in Fermi-LAT observations
- GRB 190720A: Fermi GBM detection
- GRB 190719C: Fermi GBM detection
- GRB 190719C: Swift-XRT refined Analysis
- LIGO/Virgo S190720a: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- GRB 190719C: NOT candidate optical afterglow and host
- LIGO/Virgo S190718y: No counterpart candidates in Fermi-LAT observations
- GRB 190718A: Swift-XRT refined Analysis
- LIGO/Virgo S190718y: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 190714A: an X-ray flare from 2E 1624.6+1504/UCAC4 525-061488
- GRB 190708B: confirmation of the X-ray afterglow