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.
Advanced Search Examples (click to copy):
subject:"Swift"body:"GRB"submitter:"Judith Racusin"3850 results found.
- GRB 130912A: 5.8 GHz VLA upper limit
- GRB 130831A: Continued Skynet/PROMPT-SSO, PROMPT-CTIO and Yerkes-41 detections
- GRB 130831A: T100 observations
- GRB 130831A: THO optical observation
- GRB 130831A: Optical Observations via Virtual Telescope
- GRB 130831A: Montarrenti Observatory optical observations
- GRB 130831A: Skynet/PROMPT-SSO detections
- GRB 130831A: Swift detection of a burst with an optical counterpart
- GRB 130829A: AAO optical observations
- GRB 130829A: NOT optical observations
- GRB 130623A: GROND detection of the optical/NIR afterglow
- GRB 130806A: MITSuME Okayama upper limits
- IPN localization of GRB 130804A
- SGR 1745-29 (Swift trigger 565443), Swift-BAT refined analysis
- Trigger 565443: Swift detection of a burst from SGR J1745-29
- GRB 130803A, Swift-BAT refined analysis
- GRB 130803A: Enhanced Swift-XRT position
- GRB 130803A: Swift detection of a burst
- GRB 130722A: Faulkes Telescope South optical candidate
- Fermi GRB 130702A: Swift XRT and UVOT observations
- Swift Trigger 558631 is not a real source
- Fermi/GBM observation of the Soft Gamma Repeater SGR J1550-5418
- GRB 130612A: ISON-NM optical observations
- GRB 130608A: Further Swift-BAT analysis
- GRB 130608A: Swift-BAT refined analysis
- GRB 130608A: Swift detection of a burst
- GRB 130606A: EVLA detection
- Trigger 557640: Swift detection of burst from SGR J1745-29
- GRB 130606A:T100 observations
- GRB130606A: Montarrenti Observatory afterglow detection
- Virtual Telescope observations of GRB 130606A
- GRB 130606A: IRSF NIR Observation
- GRB 130606A: NOT afterglow detection
- GRB 130605A: Swift detection of a burst
- GRB 130603A: MITSuME Okayama Optical Observation
- Fermi Trigger 130507.091 - Detection of a SGR-like Burst
- GRB 130504C: Suzaku WAM observation of the prompt emission
- GRB 130427A: Amateur observations from Sweden
- Refined IPN Triangulation of GRB 130502B
- GRB 130505A, Swift-BAT refined analysis
- Konus-Wind observation of GRB 130504C
- Swift/UVOT observations of GRB130505A
- GRB 130505A: iTelescope T12 optical observations
- GRB 130505A: Enhanced Swift-XRT position
- GRB 130505A: MAXI/GSC detection
- GRB 130505A: Swift detection of a burst with optical afterglow
- GRB 130427A: Non-observation of VHE emission with HAWC
- GRB 130427A: KAIT optical observations
- GRB 130427A: SARA-N optical observations
- GRB 130427A: MITSuME Ishigakijima Optical Observation after 2 days
- GRB 130427A: Challis Observatory optical observations
- GRB 130427A: Continued Skynet/PROMPT Observations
- GRB 130427A: further GMG observations
- GRB 130427A: SARA-N detection
- GRB 130427A: MITSuME Okayama and Ishigakijima Optical Observation after 1 day
- GRB 130427A: Optical Observations
- GRB 130427A: Swift detection of a very bright burst with a likely bright optical counterpart
- Trigger 554491: Swift detection of a spike possibly from Sgr A*
- GRB 130420A: ROTSE-III data analysis
- GRB 130420A: Early RAPTOR Simultaneous Multi-Color Observations
- Swift Trigger 554135 is probably not a GRB or transient
- GRB 130420A: ROTSE-III Detection of Optical Counterpart
- GRB 130420A: Swift detection of a burst with an optical counterpart
- GRB 130419A: Swift detection of a burst
- Konus-Wind observation of GRB 130408A
- GRB 130211A: Retraction of afterglow candidate
- Konus-Wind observation of GRB 130320B
- IPN Triangulation of GRB 130320B (very long/bright)
- Swift XRT observations of GRB 130310A
- GRB 130306A: Swift detection of a burst
- GRB 130305A: Fermi GBM observation
- GRB 121128A: optical observations in Mondy observatory
- SGR 1806-20 outburst (trigger 549841), Swift-BAT refined analysis
- Trigger 549841: Swift detection of SGR1806-20
- IPN Triangulation of GRB 130219A
- GRB 130215A: Additional P200 NIR observations
- GRB 130215A: P60 Observations
- Swift/BAT trigger 547142 is new source Swift J1753.7-2544
- Swift Trigger 547142: a probable Galactic source
- GRB 121229A: VLT/X-shooter redshift
- GRB 121229A: MAXI/GSC detection
- GRB 121229A: GROND detection of the afterglow
- Swift-BAT refined analysis of SGR 1E 1841-045 (Trigger=543763)
- Trigger 543763: SGR 1E 1841-045: Swift detection of a soft gamma repeater burst (aka Kes 73)
- GRB 121211A: MITSuME Okayama Optical Observation
- GRB 121127A: Suzaku WAM observation of the prompt emission
- GRB 121128A: optical observation in Mondy observatory
- IPN Triangulation of GRB 121127A (short/hard)
- GRB 121123A: Swift/UVOT Observations
- GRB 121123A: Swift-XRT refined Analysis
- GRB 121123A: NOT optical observations
- GRB 121123A: Swift detection of a burst with optical counterpart
- GRB 121108A: MITSuME Ishigakijima upper limits
- GRB 121108A: Swift detection of a burst
- GRB 121027A - Gemini South spectroscopy
- GRB 121029A: Fermi GBM detection
- Swift Quick-look and HEASARC will be offline for due to hurricane Sandy
- GRB 121027A: Swift detection of a burst
- GRB 121011A: early optical light curve
- GRB 121011A: optical observations