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"20378 results found.
- Faulkes Telescope South observations of GRB 071001
- GRB 071001: Swift detection of a burst
- VLA observation of GRB 070923
- GRB 070911, SMARTS optical/IR afterglow observations
- GRB070925: Swift-XRT Afterglow confirmation
- GRB 070925: Gemini South Imaging
- GRB 070920B: ROTSE-III Early Optical Limits
- GRB 070920B: TAROT La Silla observatory optical observations
- INTEGRAL ToO observations of SGR1806-20
- GRB 070920B: NOT optical observations
- GRB 070920: TAROT Calern observatory optical observations
- SGR1806-20: Swift-BAT detection of enhanced activity
- GRB 070917: P60 Observations
- GRB 070917: MITSuME Akeno Ic upper limit
- GRB 070917: R band observations
- GRB 070913: Swift-XRT detection of the possible X-ray afterglow
- GRB 070809: The Swift evidence for the SHB nature of this burst
- GRB 070913: Swift-BAT refined analysis
- GRB 070913: SMARTS optical/IR observations
- GRB 070913: TAROT La Silla observatory optical observations
- Swift-BAT Notices back to autonomous real-time distribution
- GRB 070911: PAIRITEL IR Observations
- GRB 070911: Swift detection of a burst
- GRB 070809: Confirmation of optical transient
- Candidate Orphan GRB Optical Transient in IC 4779
- Las Campanas observations of possible TAROT GRB transient near IC
- Orphan GRB candidate in IC 4779 at TAROT La Silla observatory
- GRB 070824 - Combined SuperAGILE/IPN Localization
- Konus-Wind observation of very bright GRB 070821
- GRB 070731: Swift/UVOT Upper Limit
- IPN Localization of GRB 070821 (long, very bright)
- GRB 070805: UVOT afterglow candidate retraction
- GRB 070810A: ROTSE-III Refined Analysis
- GRB 070810B : Faulkes Telescope South Observations
- GRB 070810A: Continued Keck Imaging
- GRB 070810B: Keck spectroscopy of possible host galaxies
- GRB070810B: Swift/UVOT Upper Limits
- GRB 070810B: XRT refined analysis
- GRB 070810B: Xinglong TNT optical Upper Limit
- GRB070810B: Optical observations with KANATA
- A giant outburst from Cygnus X-1 detected by Konus-Wind and Suzaku-WAM
- GRB 070809: Swift/UVOT Upper Limits
- VLA upper limit on the short hard burst GRB 070729
- No radio detection in superAGILE burst 070724B
- GRB 070809: Keck Imaging
- GRB 070810: enhanced Swift-XRT position
- GRB 070810: Swift/UVOT Optical Counterpart
- GRB 070808: Swift/UVOT upper limits
- GRB 070809: Swift detection of a short burst
- GRB 070808 : Faulkes Telescope South Observations
- GCN Swift XRT update position notices and enhanced position circulars
- GRB 070808: Swift XRT refined analysis
- GRB 070808: Xinglong TNT optical Upper Limit
- GRB070808: Optical observations with KANATA
- GRB070808 - SDSS Pre-Burst Observations
- GRB 070808: ROTSE-III Optical Limits
- GRB070805 XRT and UVOT afterglow candidate
- GRB070612A: Radio upper limit from GMRT
- Swift/UVOT observations of GRB070805
- UVOT observations of SAXJ1810.8-2609
- Swift detection of a outburst from SAX J1810.8-2609
- VLA non-detection of GRB 070721B
- GRB 070802: REM optical observations
- GRB 070802: Swift-XRT refined analysis
- GRB070802: Swift/UVOT upper limits
- GRB 070802: V-band detection of the candidate afterglow
- GRB 070802: GROND J band candidate
- Swift/UVOT detection of GRB070714B
- AGILE-ACS position for the SGR 1806-20 July 27 burst
- VLA upper limit on short hard burst GRB 070714B
- GRB070729: Swift/UVOT upper limits
- GRB 070729: Swift-XRT refined analysis
- GRB 070724B: P60 Observations
- GRB 070724B: Swift/UVOT Upper limits
- GRB 070721A: optical observations
- GRB 070724A: further VLT observations
- Four radio sources in Swift-XRT error box of GRB 070724
- GRB 070724: P60 and Gemini Observations
- GRB 060814 - Keck host detection and redshift
- Swift/UVOT refined analysis of GRB070724
- GRB 070724: Swift-XRT Team refined analysis
- GRB 070721B: further observations and analysis
- GRB 070724: Swift detection of a burst
- GRB 070714B: Keck observations
- Swift/UVOT Observations of GRB070721A
- GRB 070721B : Faulkes Telescope South observations
- GRB 070721A : Faulkes Telescope South optical limit
- GRB 070721A: Swift/XRT refined analysis
- GRB 070721A, Swift-BAT refined analysis
- GRB070721B: A bright UVOT candidate
- GRB070714B: TNG NIR observations
- GRB 070714A: Swift/UVOT Upper limits
- GRB 070714B: Swift/UVOT Upper Limits
- GRB 070714B: Swift-BAT spectral lag for the SHB
- GRB 070714B: confirmation of optical afterglow
- GRB 070616: No Evidence for I Band Afterglow
- GRB 070714A: Swift XRT refined analysis
- GRB070714B: Swift-XRT refined analysis
- GRB 070714 : Liverpool Telescope optical counterpart ?
- GRB 070714: Swift detection of a bright burst, possibly short