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"4255 results found.
- GRB 070809: ROTSE-III Optical Limits
- GRB 070808: Xinglong TNT optical Upper Limit
- GRB070808: Optical observations with KANATA
- GRB 070808: Swift detection of a burst
- Swift detection of a outburst from SAX J1810.8-2609
- VLA non-detection of GRB 070721B
- AGILE-ACS position for the SGR 1806-20 July 27 burst
- Intense burst from SGR 1806-20 detected on July 27
- GRB 070326: Detection of first burst from BAT Slew Survey (BATSS)
- GRB 070714: Swift detection of a bright burst, possibly short
- GRB 070628: Watcher Observations
- OT20050728 was not an optical GRB afterglow
- GRB 070616: Swift detection of a burst
- GRB 070612A: P60 Confirmation of Afterglow and An Underlying, Nearby
- GRB 070611: Swift/UVOT Observations
- GRB 070611: ROTSE-III Detection of Late Rising Optical Counterpart
- GRB 070611; Swift-XRT position
- Swift trigger 280447 is probably a Galactic transient
- GRB 070518: MARGE Observations
- GRB070521: P200 Observations
- GRB 070508: Suzaku/WAM observation of the prompt emission
- GRB 070507: Swift detection of a possible cosmic ray shower event or a possible burst
- GRB070429B: VLT observations
- GRB070429B: possible host galaxy detection
- Konus-Wind observation of GRB 070420
- GRB 070420 Swift-BAT Refined Analysis
- Suzaku ToO observation of SGR 1806-20
- INTEGRAL ToO Observation of SGR1806-20
- long burst from SGR 1806-20 detected on March 26
- Short-Hard GRB 070209: PROMPT Observations
- GRB 070318: Swift detection of a burst with an optical afterglow
- GRB 070224: SARA upper limit
- GRB 070224: MASTER-Net refind analysis
- GRB 070224: MASTER-VWF-Kislovodsk observations
- GRB 070201: clarification on localization and Konus-Wind spectra
- IPN localization of very intense short GRB 070201
- GRB 070208: Swift detection of a burst
- GRB 070125: further AAVSO optical observations
- GRB 070125: Continued P60 Observations
- GRB 070110: Continued Detection and Request for Ground Followup
- GRB 061201: Nearby Galaxy Cluster Abell 995 is at z=0.0865
- Retractions of previous Swift-BAT triggers
- GRB061222a: optical observations
- GRB 061222B: MITSuME Akeno optical upper limits
- GRB 061222A: Prompt ROTSE-III Optical Limits
- GRB 061201: Magellan Redshift of nearby Abell cluster
- Swift-BAT Trigger 250908 is a Cosmic Ray Shower event
- GRB061121, optical observation
- GRB 061121: Swift detection of a bright burst with an optical counterpart
- GRB061019: second epoch CrAO observations
- GRB 061028: Swift/XRT Astrometry Correction
- GRB 061028: Optical R passband observations
- GRB 061028: Futher P200 Observations
- GRB 061028: Swift/UVOT Observations
- GRB 061028: Swift detection of a burst
- GRB 061027: Swift detection of a possible burst
- GRB061019: optical observations
- GRB 061019: SMARTS afterglow confirmation
- GRB 061019: REM K-band candidate afterglow
- GRB061019: Swift/XRT position
- GRB 061007: Suzaku/WAM observation of the prompt emission
- GRB 061007: Swift-BAT refined analysis
- GRB 061007: Swift detection of a burst with an optical counterpart
- GRB 061002: Swift detection of a burst: CORRECTED CONTENT
- GRB 061002: Swift detection of a burst
- GRB 060929: TNG K-band observations
- GRB060929: Optical limit
- GRB 060729: An update on the late-time Swift observations
- GRB 060923A: Schedule of Spitzer Space Telescope Observations
- GRB 060926: Swift detection of a burst
- GRB 060923C: Keck Observations
- Swift detects a hard X-ray burst from AXP CXOU J164710.2-455216
- GRB 060919, Swift-BAT refined analysis
- GRB060904b optical detections (delayed report due to internet outage)
- GRB 060904B: RTT150 optical observations
- Two bright bursts from SGR 1806-20 detected with IBAS
- GRB 060825: VLA observations
- GRB060729: analysis of XMM-Newton observation
- GRB 060813: Swift XRT refined analysis
- Image of the dust-scattering halo around SGR 1806-20
- Second VLA limit on new radio point source in SGR 1806-20
- A dust-scattering halo detected around SGR 1806-20
- GRB060714: optical observations
- GRB060807: Optical limiting magnitudes
- VLA Upper Limit on Outburst of SGR 1806-20
- GRB060806 is similar to previous activity of SGR1806-20
- GRB 060728: Upper limits of the X-ray emission
- GRB 060729: Swift/UVOT Detections
- GRB 060729: Swift/UVOT Observations
- GRB 060729: Swift detection of a burst with an UVOT optical counterpart
- GRB 060728, SMARTS optical/IR observations
- GRB060614 ATCA Radio Limits
- GRB060526: optical observations
- GRB 060515: Upper Limit on Host Galaxy
- GRB050124: Possible Host Galaxy
- GRB 060614: Swift/UVOT Observations
- BAT Trigger #214277 is SGR 1900+14
- GCN 060607: Swift-UVOT obswervations.
- GRB 060607: REM NIR afterglow
- GRB 060607: Swift detection of a burst with bright optical counterpart