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"19565 results found.
- IPN Triangulation of GRB 170921B
- INTEGRAL SPI-ACS observation of AMON IceCube-170922A
- GRB 170921A: RATIR Optical Afterglow Detection and NIR Observations
- LIGO/Virgo G298048: SRT observations of SSS17a in NGC 4993
- GRB 170921A: Swift/UVOT Upper Limits
- GRB 170921A: NOT optical observations
- LIGO/Virgo G298048: LCO FLOYDS and Gemini Spectroscopy
- GRB 170921A: Nanshan optical upper limit
- GRB 170921A: Enhanced Swift-XRT position
- GRB 170921A: MITSuME Okayama upper limits
- GRB 170921A: Swift-XRT refined Analysis
- GRB 170921A: TAROT Calern observatory optical observations
- GRB 170921A: Swift detection of a burst
- LIGO/Virgo G298048: ATCA monitoring of SSS17a in NGC 4993
- LIGO/Virgo G298048: Milliarcsecond imaging of the NGC 4993 central radio source
- LIGO/Virgo G298048: ATLAS pre-discovery limits 601 to 16 days before first detection of SSS17a/DLT17ck
- LIGO/Virgo G298048: AST3-2 observations of SSS17a/DLT17ck from Antarctica
- LIGO/Virgo G298048: ATCA monitoring of SSS17a in NGC 4993
- GRB 170912B: Swift/UVOT Upper Limits
- GRB 170912A: Swift-XRT refined Analysis
- LIGO/Virgo G299232: Khureltogot observations
- GRB 170912A: Swift/UVOT Upper-Limits
- GRB 170912B: Enhanced Swift-XRT position
- LIGO/Virgo G299232: Pierre Auger Observatory follow-up
- LIGO/Virgo G298389: Pierre Auger Observatory neutrino follow-up
- GRB 170912B: Swift detection of a burst
- GRB 170912A: Enhanced Swift-XRT position
- GRB 170912A: Swift detection of a burst
- LIGO/Virgo G298048: VLBA upper limits at 8.7GHz for the GW counterpart SSS17a/DLT17ck on August 20-21 UT
- GRB 170906A: Swift/UVOT Detection
- GRB 170906B: Swift/UVOT Upper Limits
- LIGO/Virgo G299232: Swift-XRT sources
- GRB 170906C: optical observations
- GRB 170906C: COATLI Observations
- GRB 170906C: Swift/UVOT Upper Limits
- GRB 170906C: Enhanced Swift-XRT position
- GRB 170906C: Swift-XRT observations
- GRB 170906A: REM optical/NIR observations
- GRB 170906A: Enhanced Swift-XRT position
- GRB 170906B: Enhanced Swift-XRT position
- GRB 170906B: Swift detection of a burst
- GRB 170906A: Swift detection of a burst with an optical afterglow
- IPN Triangulation of GRB 170904A (long/very bright)
- LIGO/VIRGO G298048: Radio detection of SSS17a at 6 GHz with the VLA
- LIGO/VIRGO G298048: Radio detection of SSS17a at 3GHz with the VLA/JAGWAR
- LIGO/Virgo G299232: Maidanak observations of optical transient SwiftJ014008.5+343403.6
- LIGO/Virgo G299232: LOFAR follow-up
- GRB 170827A: LCO Observations
- GRB 170903A: Swift/UVOT Upper Limits
- GRB 170903A: UAFO /ISON optical upper limit
- LIGO/Virgo G298048: e-MERLIN upper limits on 5 GHz compact emission from SSS17a
- LIGO/Virgo G298048: ATCA monitoring of SSS17a in NGC 4993
- LIGO/Virgo G299232: RoboPol observations of MASTER OT J033744.97+723159.0
- GRB 170903A: MITSuME Okayama upper limits
- GRB 170903A: Host galaxy redshift from OSIRIS/GTC
- LIGO/Virgo G298048: Chandra X-ray Update on GW170817
- GRB 170903A: Enhanced Swift-XRT position
- GRB 170903A: Nanshan optical upper limit
- GRB 170903A: Swift-XRT observations
- Swift Triggers on MAXI J1535-571
- GRB 170902A: Enhanced Swift-XRT position
- LIGO/Virgo G297595: DECam observations of BBH merger region of interest
- GRB 170902A: Swift detection of a burst or possible Galactic transient
- LIGO/Virgo G298048: Chandra monitoring of the X-ray emission from SSS17a
- LIGO/Virgo G298048: Continued X-ray monitoring and X-ray detection of GW170817 [erratum]]
- LIGO/Virgo G298048
- LIGO/Virgo G298048: Hubble Space Telescope observations
- LIGO/Virgo G299232: GRAWITA Asiago optical observations
- LIGO/Virgo G299232: continued WHT observations of the field of SwiftJ014008.5+343403.6
- LIGO/Virgo G298048: Discovery of X-ray emission from SSS17a in NGC4993
- GRB 170830A: iTelescope optical observations
- LIGO/Virgo G299232: HAWC follow-up
- LIGO/Virgo G299232 : RATIR Optical and NIR Observations of Swift UVOT source
- LIGO/Virgo G299232: WHT non-detection u-band optical transient
- LIGO/Virgo G299232: Liverpool Telescope observations
- LIGO/Virgo G299232: observations of the optical Transient Discovered by Swift/UVOT
- IPN Triangulation of GRB 170826B
- LIGO/Virgo G299232: PIRATE observations of MASTER OT J033744.97+723159.0
- LIGO/Virgo G299232/PGWB170825.55: early MASTER observations of the Swift UVOT source position
- LIGO/Virgo G298048: ALMA observations
- LIGO/Virgo G299232: GRAWITA Asiago/Copernico Telescope observations
- GRB170827A: Further GROND follow-up observations
- LIGO/Virgo G299232: COATLI Observations of MASTER OT J033744.97+723159.0
- IPN Triangulation of GRB 170827B (short)
- LIGO/Virgo G298936: HAWC follow-up
- GROND observations of GRB170827A
- GRB 170827A: ePESSTO NTT afterglow candidate
- GRB 170823A: TAROT Calern observatory optical observations
- LIGO/Virgo G299232: OVRO-LWA simultaneous low frequency radio observations of localization region
- LIGO/Virgo G299232: LOFAR follow-up
- GRB 170827A: Swift/UVOT Upper Limits
- GRB 170827A: REM optical/NIR observations
- GRB 170827A: Swift detection of a burst
- LIGO/Virgo G299232: CALET Observations
- LIGO/VIRGO G299232: Fermi GBM Observations
- LIGO/Virgo G299232 : Fermi-LAT search for high-energy gamma-ray counterpart
- LIGO/Virgo G298389: HAWC follow-up
- LIGO/Virgo G298936: CALET Observations
- GRB 170820A CALET Gamma-Ray Burst Monitor detection
- LIGO/Virgo G299232: Swift/BAT data search