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').
49 results found.
- IceCube-190504A: Swift-XRT Follow-up Observations
- LIGO/Virgo S190426c: Swift-XRT sources
- Swift Trigger 895479: Detection of GRO J2058+42
- Swift Trigger 895257: Detection of GRO J2058+42 in outburst
- Swift detection of LS I +61 303
- Swift Trigger 894268: Detection of GRO J2058+42 in outburst
- Swift Trigger on AXP CXOU J164710.2-455216/PSR J1647-4552
- Swift trigger 781740: Further analysis from Swift and Fermi/GBM
- Swift Trigger 781740 is not a burst
- Swift Trigger on AXP CXOU J164710.2-455216/PSR J1647-4552
- Trigger 779762: Swift detection of Vela X-1
- Further Swift-XRT observations of IceCube 170922A
- IceCube-170922A: Swift-XRT observations
- LIGO/Virgo G299232: Swift-XRT sources
- LIGO/Virgo G297595: Swift-XRT sources
- Swift Trigger on AXP CXOU J164710.2-455216
- Swift triggered on SAX J1806.5-221
- IceCube-170321A: 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 G270580: Swift-XRT sources
- Swift Trigger 707545 is likely 4U 1850-03/GS1843-02
- Swift follow up of IceCube-160731A
- Swift Trigger 701668 is probably not an astrophysical event
- Swift detects GX 301-2 in very high state
- LIGO/Virgo G211117: Further Swift-XRT sources
- LIGO/Virgo G211117: Further Swift-XRT sources
- Trigger 668877: Swift detection of V 404 Cyg
- LIGO/Virgo G211117: Further Swift-XRT sources
- LIGO/Virgo G211117: Swift-XRT sources
- Trigger 650221: Swift detection of a IGR J00291+5934
- Swift triggers again on V404 Cyg
- Swift Trigger 644520 is V404 Cyg
- Swift detection of SAX J1808.4-3658
- GRB 150220A: Optical observations at Kyiv comet station
- GRB 150301C: XRT detection of a potential counterpart of BAT trigger 633105
- Trigger 632888: Swift detection of the magnetar 4U 0142+61
- Trigger 631747: Swift detection of 4U 0614+09
- Trigger 630047: Swift detection of 1RXS J180408.9-342058
- Swift detection of 4U 1700+24 (= V* V934 Her)
- Trigger 618634: Swift detection of Vela X-1
- Swift detection of outburst from 4U 1700+24
- Swift detection of SAX J1712.6-3739
- Swift trigger 609139 is probably 4U 1850-03
- Swift trigger 600114 is not an outbursting X-ray source
- Swift detection of a bright X-ray source in M31
- GRB 140221A: Results from Swift XRT tiled observations