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"8476 results found.
- LIGO/Virgo G194575: Identification of a GW CBC Candidate
- GRB 151022A: Swift detection of a burst
- GRB 151021A: Swift detection of a burst
- GRB 151004A: Swift-XRT follow-up observations
- Konus-Wind observation of GRB 151006A
- GRB 151006A: Swift-BAT refined analysis
- GRB 151006A: Fermi GBM detection
- GRB 151006A: Swift detection of a burst
- LIGO/Virgo G184098: Ongoing gravitational-wave analysis
- GRB 151001B: Swift detection of a burst
- GRB 151001A: Swift detection of a burst with an optical counterpart
- LIGO/Virgo G184098: spectral classification of PS15cci
- GRB 150925A: Swift detection of a burst
- LIGO/Virgo G184098: TAROT network optical observations
- LIGO/Virgo G184098: Fermi-GBM ground-based follow-up
- LIGO/Virgo G184098: iPTF Optical Transient Candidates
- LIGO/Virgo G184098: TAROT La Silla Observatory optical observations (TZAC)
- LIGO/Virgo G184098: Burst candidate in LIGO engineering run data
- GRB 150915A: GROND detection of an optical counterpart candidate
- GRB 150915A: Swift detection of a burst
- GRB 150911A: WHT optical imaging
- GRB 150912A: Swift ToO observations
- GRB 150911A: Swift detection of a burst
- GRB 150910A: NOT observations of the afterglow
- GRB 150910A: Swift detection of a burst with an optical afterglow
- Short GRB 150906B: proximity to NGC 3313 galaxy group
- GRB 150907B: Swift-BAT refined analysis
- GRB 150907B: GROND Upper Limits
- GRB 150907A: Tiled Swift observations
- ANTARES neutrino Alert150901.32 alert and Swift XRT counterpart: MASTER optical observations and new possible candidate
- ANTARES neutrino detection: Optical/NIR spectroscopy of the Swift/XRT counterpart candidate from NOT
- GRB 150902A: Swift ToO observations
- GRB 150818A: Spectroscopic confirmation of the SN from GTC
- GRB 150831A: Swift detection of a short burst
- GRB 150821A: Fermi GBM detection
- GRB 150821A: Swift detection of a burst with an optical afterglow
- GRB 150819A: Swift detection of a burst
- GRB 150818A: Swift/UVOT candidate afterglow
- GRB 150817A: P60 Observations
- GRB 150818A: Swift detection of a burst
- GRB 150817A: Continued RATIR Observations, Revised Candidate
- GRB 150817A: RATIR Optical Afterglow Candidate
- Swift Trigger 652046 is probably not a GRB
- GRB 150811A: Swift-BAT refined analysis
- GRB 150811A: KAIT optical candidate
- GRB 150811A: Swift detection of a burst
- Fermi GBM GRB Trigger 460608875: iPTF P48 Observations
- GRB 150728A: TNG optical observations
- Fermi GBM GRB Trigger 458852670: iPTF P48 Observations
- GRB 150721A (Fermi GBM Trigger 459150552): iPTF P48 Observations
- GRB 150801B: Swift detection of a burst
- GRB 150801A: Tiled Swift observations
- GRB 150728A: TSHAO optical observations
- GRB 150728A: Swift detection of a GRB
- GRB 150727A: Swift-BAT refined analysis
- GRB 150727A: Watcher optical upper limit
- GRB 150727A: Fermi GBM detection
- GRB 150727A: Swift detection of a burst with an optical counterpart
- GRB 150724B: Swift ToO observations
- Trigger 650221: Swift detection of a IGR J00291+5934
- GRB 150724A: Swift detection of a burst
- Swift Trigger 649706: a possible GRB or bright Galactic transient
- GRB 150716A: P60 Candidate Optical Afterglow
- GRB 150716A: RATIR Optical Observations
- GRB 150716A: Swift detection of a burst
- Trigger 649113: Swift detection of SGR 1E 1841-045
- GRB 150711A: Swift detection of a burst
- GRB 150710B: Swift ToO observations
- MASTER OT Detection during Fermi Trigger 458235025 inspection
- GRB 150710A: host galaxy for Swift XRT second candidate
- Swift trigger 648437: A GRB or a burst from 1RXS J125754.7+141850
- GRB 150702A: Swift ToO observations
- Swift Trigger 647642 is probably not an astrophysical source
- GRB 150627A: Swift ToO observations
- GRB 150626B: Swift detection of a burst
- GRB 150626A: Swift detection of a burst
- GRB 150622A: Tiled Swift observations
- Swift Trigger 645340: a possible GRB
- Konus-Wind observation of Galactic transient V404 Cyg in outburst
- GRB 150616A: Swift detection of a burst
- Swift trigger 643949 is V404 Cyg
- GRB 150615A: Swift detection of a burst
- Trigger 643078: Swift detection of H1743-322
- GRB 150608A: Tiled Swift observations
- GRB 150607A: Swift detection of a burst with an optical counterpart
- Swift Trigger 642453: a possible GRB
- GRB 150530B: Swift ToO observations
- GRB 150530A: Swift detection of a burst
- GRB 150527A: Swift detection of a burst
- GRB 150523A: Swift ToO observations
- GRB 150523A: LCOGT FTS afterglow confirmation
- GRB 150523A: LCOGT Cerro-Tololo optical afterglow candidate
- GRB 150523B: Swift ToO observations
- Swift trigger 641332 is probably not an astrophysical source
- GRB 150518A: Mondy optical observations
- GRB 150518A: Tiled Swift observations
- GRB 150514A: Fermi GBM Detection
- GRB 150514A: Swift ToO observations
- GRB 150512A: iPTF Optical Observations
- Konus-Wind observation of GRB 150510A