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"19566 results found.
- GRB 200512A: Swift/UVOT Upper Limits
- GRB 200512A: Enhanced Swift-XRT position
- GRB 200512A: Swift detection of a burst
- IceCube-200512A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- IPN triangulation of a bright burst from SGR 1935+2154 on 2020-05-10 at 06:12 UT
- GRB 200509A: GROWTH-India r band upper limits
- GRB 200509A: Swift/UVOT Detection
- GRB 200509A: Enhanced Swift-XRT position
- GRB 200509A: Zadko observatory - Gingin optical upper limits
- GRB 200509A: Swift detection of a burst with a possible optical counterpart
- Swift Detection of a burst from SGR Swift J1818.0-1607
- GRB 200424A: Swift-XRT afterglow detection
- Fermi GBM observation of a flare from the magnetar SGR 1806-20
- SGR 1935+2154: INTEGRAL hard X-ray counterpart of radio burst
- Konus-Wind observation of a very intense bursting activity of SGR 1935+2154
- IceCube-200425A: No significant detection in HAWC
- Fermi-LAT Gamma-ray Observations of IceCube-200425A
- IceCube-200425A: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
- GRB 200425A: Swift/UVOT Upper Limits
- GRB 200425A: Enhanced Swift-XRT position
- GRB 200425A: Swift detection of a burst
- GRB 200424A: Swift ToO observations
- IPN Triangulation of a bright burst from SGR 1935+2154
- GRB 200410A: Liverpool Telescope First Hour Observations
- Fermi-LAT Gamma-ray Observations of IceCube-200421A
- IceCube-200421A: No significant detection in HAWC
- IceCube Alert 200421.02: Global MASTER-Net observations report
- IceCube-200421A: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
- GRB 200412B: continued Mondy and Terskol optical observations
- GRB 200412B: continued Terskol optical observations
- GRB 200412B: continued AbAO, Mondy, TSHAO, Terskol optical observations
- GRB 200410A: Optical upper limit
- GRB 200416A: Swift/UVOT Detection
- GRB 200412B: Swift XRT confirmation of afterglow and UVOT upper limits
- GRB200412B: GROWTH India detection of afterglow
- GRB 200412B: continued Tautenburg observations
- GRB 200416A: Swift detection of a burst with an optical afterglow
- GRB 200411A: Chandra observations indicative of temporal steepening
- IPN triangulation of GRB 200415A (possible Magnetar Giant Flare in Sculptor Galaxy?)
- GRB 200412B: Mondy optical observations
- GRB 200412B: continued Tautenburg observations
- GRB 200412B: Tautenburg observations
- GRB 200412B: contunued AbAO optical observations
- GRB 200412B: SAO RAS observations of OT
- IceCube-200410A: No significant detection in HAWC
- GRB 200412B: Tautenburg observations
- GRB 200412B: AbAO optical observations
- GRB 200412B: Swift-XRT afterglow detection
- GRB 200412B: Tiled Swift observations
- GRB 200411A: Swift-BAT refined analysis
- Fermi-LAT Gamma-ray Observations of IceCube-200410A
- GRB 200411A: Swift-XRT refined Analysis
- GRB 200411A: Swift/UVOT Upper Limits
- GRB 200411A: Enhanced Swift-XRT position
- IceCube-200410A: Possible associated excess in INTEGRAL SPI-ACS prompt observation
- GRB 200411A: Swift detection of a short burst
- IceCube-200410A - IceCube observation of a high-energy neutrino candidate event
- GRB 200410A: Swift/UVOT Detection
- LIGO/Virgo S200224ca: Swift XRT observations, 8 X-ray sources
- GRB 200410A: Swift-XRT refined Analysis
- GRB 200410A: Enhanced Swift-XRT position
- GRB 200410A: Swift detection of a burst with a possible optical counterpart
- GRB 200405B: ATCA follow-up and ASKAP limits on pre-burst radio emission
- GRB 200409A: Enhanced Swift-XRT position
- GRB 200409A: Swift detection of a burst with an optical counterpart
- GRB 200405B: Swift ToO observations
- GRB 200405B: Swift/BAT-GUANO detection and *possible* arcminute localization of a short GRB
- GRB 200325B: Optical upper limit
- GRB 200325B: Tautenburg observations
- IPN triangulation of GRB 200327A (short)
- GRB 200327A: AGILE/MCAL observations
- Fermi trigger No 607035413: Global MASTER-Net observations report
- GRB 200325B: Swift-XRT and UVOT observations
- GRB 200325B: Mondy and CrAO observations, Master MASTER OT J111012.51+274912.8 confirmation
- GRB 200325B: Swift ToO observations
- GRB 200325B: MASTERt OT detection
- GRB 200324A: AROMA-N Optical Observation
- GRB 200325A: Swift/BAT detection and probable arcminute localization of a short GRB from GUANO
- GRB 200324A:: TSHAO optical upper limit
- GRB 200324A: Swift/UVOT Upper Limits
- GRB 200325A: AGILE/MCAL observations
- GRB 200324A: Konkoly Obs. optical upper limit
- GRB 200324A: NOT optical upper limit
- GRB 200324A: Tautenburg observations
- GRB 200324A: Enhanced Swift-XRT position
- GRB 200324A: Swift detection of a burst
- LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC-F30 observations
- Chandra observations of GW170817 at 2.5 years since merger (All epochs 4 of 4)
- GW170817: Continued X-ray emission detected with Chandra at 940 days post-merger
- LIGO/Virgo S200316bj : No significant candidates in TAROT - FRAM - GRANDMA observations.
- LIGO/Virgo S200316bj: no counterpart candidate in SVOM/GWAC observations
- LIGO/Virgo S200316bj: No neutrino candidates at Pierre Auger Observatory
- LIGO/Virgo S200316bj: No counterpart candidates in Fermi-LAT observations
- LIGO/Virgo S200316bj: No Counterparts in DDOTI/OAN Optical Observations
- LIGO/Virgo S200316bj: no counterpart candidates in the Swift/BAT observations
- Konus-Wind observation of GRB 200311A
- LIGO/Virgo S200316bj: No counterpart candidates in INTEGRAL SPI-ACS, and IBIS prompt observation
- LIGO/Virgo S200316bj : no neutrino counterpart candidate in ANTARES search
- Swift-BAT trigger 960986: Swift detection of a new SGR Swift J1818.0-1607
- LIGO/Virgo S200311bg: No significant counterpart candidates in Fermi-LAT observations