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"19543 results found.
- Fermi trigger 576241792 / GRB 190406B: MASTER optical observation
- GRB 190406B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 576241792)
- IPN Triangulation of GRB 190415A
- LIGO/Virgo S190412m: Palomar Gattini-IR Wide-field Infrared Follow-up
- LIGO/Virgo S190412m: GOTO optical coverage - no notable counterparts
- LIGO/Virgo S190412m: Fermi-LAT search for a high-energy gamma-ray counterpart
- LIGO/Virgo S190412m: Swift/BAT data search
- LIGO/Virgo S190412m: J-GEM optical/NIR follow-up observations
- LIGO/Virgo S190412m/G329483: ANTARES neutrino search
- LIGO/Virgo S190412m: Hobby-Eberly Telescope VIRUS observations of target galaxies.
- LIGO/Virgo S190412m: HAWC follow-up
- INTEGRAL prompt observation of S190412m
- LIGO-Virgo S190412m: AGILE preliminary analysis
- LIGO/Virgo S190408an: GROND Observations of MASTER OT J154209.55-431742.2
- IPN triangulation of GRB 190409B (short)
- IceCube-190331A: Swift-XRT Follow-up Observations
- GRB 190409A: ground analysis reveals a likely spurious event
- LIGO/Virgo S190408an: MAXI/GSC Observations
- GRB 190404C: MITSuME Akeno and Okayama optical upper limits
- LIGO/Virgo S190408an: CALET Observations
- LIGO/Virgo S190408an: TMTS Optical Observation
- LIGO/Virgo S190408an: DDOTI/OAN Optical Observations
- LIGO/Virgo S190408an: HMT optical observations
- LIGO/Virgo S190408an: MASTER 3 OT's more detection
- LIGO/Virgo ST190408an: Fermi-LAT search for a high-energy gamma-ray counterpart
- GRB 190409A: Swift detection of a possible burst
- LIGO/Virgo S190408an: SAGUARO follow-up observations
- LIGO/Virgo S190408an: MASTER OT detection
- LIGO/Virgo S190408an: Swift/BAT data search
- LIGO-Virgo S190408an: HAWC follow-up
- INTEGRAL observation of S190408an
- LIGO-Virgo GW S190408an: J-GEM optical/NIR follow-up observations
- LIGO-Virgo S190408an: AGILE MCAL observations
- GRB 190404C: Swift-XRT afterglow detection
- Fermi TriggNum 576054086 (GRB 1904204.29) / MASTER OT J071404.52+550304.2: CrAO optical observations
- GRB190404C: GROWTH-India discovery of optical counterpart
- GRB 190404B: Tiled Swift observations
- GRB 190330A: MITSuME Akeno and Okayama optical upper limits
- Trigger 896552: Swift detection of PSR B1055-52
- LIGO/Virgo: Announcing the start of Observing Run 3 (O3) and the beginning of the public gravitational-wave alert era
- Konus-Wind observation of GRB 190329A
- GRB 190331B: Swift observations of a ground-detected burst
- Fermi-LAT Gamma-ray Observations of IceCube-190331A
- GRB 190331B: Swift ToO observations
- Swift Trigger 895503 is not a GRB
- Swift Trigger 895479: Detection of GRO J2058+42
- GRB 190326A: Swift-BAT refined analysis - a soft-short GRB or an SGR
- Swift Trigger 895257: Detection of GRO J2058+42 in outburst
- GRB 190324A: Swift/UVOT Observations
- GRB 190324A: Enhanced Swift-XRT position
- Further Chandra observations of GW170817 ~581-583 days since merger
- GRB 190324A: Swift-XRT observations
- Swift detection of LS I +61 303
- Correction: Chandra observations of GW170817 ~581 days since merger
- Chandra observations of GW170817 ~581 days since merger
- Swift Trigger 894268: Detection of GRO J2058+42 in outburst
- GRB 190320A: Swift/UVOT Upper Limits
- GRB 190320A: Enhanced Swift-XRT position
- GRB 190320A: Swift-XRT observations
- GRB 190311A: Swift/UVOT Detection
- GRB190311A: OAO observations
- GRB 190311A: GMG observation
- GRB 190311A: Enhanced Swift-XRT position
- GRB 190311A: NEXT-0.6m optical afterglow detection
- GRB 190311A: Mondy optical observations
- GRB 190311A: Swift detection of a burst with optical counterpart
- GRB 190305A: Swift-XRT afterglow detection
- IPN Triangulation of GRB 190304A (long)
- GRB 190306A: Swift-XRT observations
- GRB 190306A: Tiled Swift observations
- IPN Triangulation of GRB 190305A
- GRB 190305A: MAXI/GSC detection
- GRB 190305A: Tiled Swift observations
- Trigger 890732: Swift detection of MAXI J1631-479
- INTEGRAL observation of IceCube-190221A
- IceCube-190221A: Swift-XRT Follow-up Observations
- IceCube-190221A: Fermi-LAT Gamma-ray observations
- GRB 190220B: Fermi GBM observation
- GRB 190219A: CrAO and AbAO optical upper limit
- GRB 190220B: Kitab Observatory optical upper limit
- GRB 190220A: Swift-XRT refined Analysis
- GRB 190220A: Enhanced Swift-XRT position
- GRB 190219A: NOT optical afterglow candidate
- GRB 190219A: NEXT-0.6m optical upper limit
- GRB 190220A: Swift detection of a burst with an optical counterpart
- GRB 190219A: Enhanced Swift-XRT position
- GRB 190219A: Swift detection of a burst
- Trigger 889483: Swift detection of Swift J1858.6-0814
- GRB190211A: GROWTH-India detection of optical afterglow
- GRB 190211A: Tautenburg observations
- GRB 190211A: Swift/UVOT Detection
- GRB 190211A: NOT optical observations
- GRB 180703A: VLT/MUSE host galaxy redshift measurement
- GRB190211A: MASTER Global Robotic Net optical observation
- GRB 190211A: NEXT-0.6m optical afterglow detection
- GRB 190211A: Swift detection of a burst
- GRB 190202A: Terskol 2-m optical observations
- IPN Triangulation of GRB 190206A (short/extremely bright)
- GRB 190203A: Mondy optical observations
- GRB190202A: GROWTH-India detection of optical afterglow