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').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
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.
Lucene Examples (click to copy):
subject:"Swift"body:"GRB"submitter:"Judith Racusin"87 results found.
- IceCube-250406A: Swift-XRT observations
- SVOM/sb25022102: SVOM detection of an X-ray transient
- GRB 250209A: MAXI/GSC detection (possible detection of an X-ray flare from 1RXS J145110.3+310648)
- EPWXT01709129925: Xinglong optical observations
- The EP-WXT trigger 01709129925 is likely a flaring star
- Swift-XRT observations of IceCube -241127A
- EP trigger ID 01709065118: Keck/LRIS spectroscopic observations
- EP trigger ID 01709065118: KAIT confirmation of the stellar flare
- EP trigger ID 01709065118: the X-ray transient is likely a stellar flare event
- GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
- GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT
- GRB 240905E: Swift detection of a burst
- GRB 240514E: A possible candidate BD-21 1074
- Fermi trigger No 737247400: Global MASTER-Net observations report
- IceCube-220624A: One Candidate Counterpart from Swift/XRT follow up observations
- Fermi-LAT Gamma-ray Observations of IceCube-220509A
- Fermi-LAT Gamma-ray Observations of IceCube-211125A
- MeerLICHT follow-up of GRB 211106A
- IceCube 135113_19489408.amon: Swift-XRT observations
- GRB 210222B: Swift detection of a burst with an optical counterpart
- Swift-XRT observations of IceCube-210210A
- Fermi-LAT Gamma-ray Observations of IceCube-201021A and detection of a new gamma-ray source, Fermi J1725.5+1312
- Swift-XRT observations of IceCube 201021A
- Swift-XRT observations of IceCube 200929A
- Swift-XRT observations of IceCube 200615A
- Correction to the GCN 27886: Previous bursts of 1RXS J1708-4009 (Swift trigger 975998)
- 1RXS J1708−4009: Swift-BAT refined analysis
- Swift detection of an SGR-like burst from 1RXS J1708−4009
- IceCube-200109A: Swift-XRT and UVoT Follow-up Observations
- Swift follow-up observations of IceCube-200107A: Identification of X-ray high state for 4FGL J0955.1+3551
- Fermi-LAT Gamma-ray Observations of IceCube-200107A
- Fermi-LAT Gamma-ray Observations of IceCube-190819A
- LIGO/Virgo S190728q/IceCube neutrino candidate: No counterpart candidates in the Swift-XRT Observations
- IceCube-190504A: Swift-XRT Follow-up Observations
- LIGO/Virgo S190426c: Swift-XRT sources
- IceCube-190331A - IceCube observation of a high-energy neutrino candidate event
- Swift trigger 831888: misidentification of 4U 1416-62
- Swift detection of MAXI J1820+070
- IceCube-171106A: Swift Observations
- IceCube-170922A: Swift-XRT observations
- LIGO/Virgo G299232: Swift-XRT sources
- GRB 170830A: iTelescope optical observations
- LIGO/Virgo G297595: Swift-XRT sources
- LIGO/Virgo G288732: Swift-XRT follow up of the putative LAT counterpart
- Fermi-LAT Gamma-ray Observations of IceCube-170321
- IceCube-170312A: Swift-XRT observations
- LIGO/Virgo G275697: Further Swift-XRT sources
- LIGO/Virgo G275697: Further Swift-XRT sources
- LIGO/Virgo G275697: Further Swift-XRT sources
- LIGO/Virgo G275697: Further Swift-XRT sources
- LIGO/Virgo G268556: Swift-XRT detection of ATLAS17aeu
- LIGO/Virgo G268556: Swift-XRT sources
- Fermi/LAT search for counterpart to the IceCube event 67093193 (run 127853)
- LIGO/Virgo G211117: Swift-XRT sources
- LIGO/Virgo G184098: Swift follow-up observations
- Swift-XRT observations of GRB 150710A
- Swift trigger 648437: A GRB or a burst from 1RXS J125754.7+141850
- GRB 150305A: Swift XRT confirms weak INTEGRAL event as a new GRB
- Trigger 630047: Swift detection of 1RXS J180408.9-342058
- Swift Trigger 629206 is likely 1RXS J180408.9-342058
- GRB141208.63: MASTER OT Detection During the Fermi Error Box inspection
- MAXI GRB 141029A is likely an X-ray flare from 1RXS J043657.1-161258
- GRB 140110A: Swift XRT observations
- Swift Trigger 575905/possible GRB 131026A: Swift-XRT observations
- GRB 120819A: Swift/UVOT Upper Limits
- GRB 120510A: Swift XRT and UVOT observations
- GRB 111204A: Swift/UVOT Upper Limits
- GRB 110428A : Swift-XRT observations
- GRB 110420B: Swift-XRT afterglow candidate retraction
- GRB 110213B: Swift XRT observation
- Swift-BAT trigger 431582 likely is IGR J17464-2811
- GRB 100216A: Swift/UVOT Observations
- GRB 100216A: XRT Refined Analysis
- Swift Trigger 381434 is not a GRB
- GRB 090305: Swift detection of a short burst
- GRB 080822 (SGR 0501+4516): archival optical observations
- Trigger 317393: Swift detection of a possible GRB
- GRB 060930: A long X-ray rich GRB detected by INTEGRAL
- GRB 060425: IPN localization and KW spectrum of a short, hard burst
- H4043, an unusual high-energy transient observed by HETE
- GRB 060204A: Swift XRT upper limit
- Possible GRB 040903 - further analysis
- GRB020819(=H2275): A Long Burst Localized by the HETE WXM and SXC
- BeppoSAX ALERT: Possible X-ray rich GRB011030
- GRB010214: BeppoSAX/NFI Observations
- GRB990806 BeppoSAX follow up
- BeppoSAX NFI observations of GRB 980703