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"5544 results found.
- GRB 140930A/MAXI J2259+524: MAXI-GSC detection
- GRB 140928A: GROND Afterglow Candidate
- GRB 140919A, Swift-BAT refined analysis
- GRB 140919A: GROND afterglow candidate
- GRB 140919A: Swift detection of a burst
- Swift detection of outburst from 4U 1700+24
- GRB 140916A: MITSuME Okayama upper limits
- GRB 140916B: iPTF Optical Observations
- GRB 140916A: Swift detection of a burst
- GRB 140907A: Mondy optical observations
- GRB 140907A: TShAO observations
- GRB 140907A: MASTER optical observations
- GRB 140907A: Nishi-Harima NIR Observations
- GRB 140907A: MITSuME Akeno Optical Observation
- IPN Triangulation of GRB 140906C (short/hard)
- GRB 140907A: MITSuME Ishigakijima Optical Observation
- GRB140907A: MITSuME Okayama Optical Observation
- GRB 140907A : Optical observations from Nanshan
- GRB 140906A: iPTF optical transient candidates
- GRB 140901B: Swift XRT observation
- GRB 140903A: ISON-Kislovodsk observations
- GRB 140903A: MAXI/GSC upper limit
- GRB140903A: Discovery Channel Telescope Optical Detection
- IPN Triangulation of GRB 140901A (short/hard/very intense)
- GRB 140831A: iPTF observations of a possible short burst detected by Fermi GBM
- GRB 140815A: GROND afterglow candidate
- Swift trigger 609139 is probably 4U 1850-03
- GRB 140809A (FERMI trigger 429246673): MASTER follow-up inspection
- GRB 140808A: optical afterglow candidate iPTF14eag
- GRB 140801A: GROND Afterglow detection, unbroken decay
- GRB 140709B: TShAO optical upper limit
- GRB 140716A: GROND confirmation of the afterglow
- GRB 140719A: FTS observations
- Swift detection of UX Ari
- Fermi GBM Observations of SGR 1935+2154
- GRB 140709A: Continued RATIR Optical and NIR Observations
- GRB 140709B: update of Khureltogot optical upper limit
- GRB 140709B: Fermi GBM detection
- GRB 140709B: Khureltogot optical upper limit
- GRB 140709A: Fermi GBM detection
- GRB 140709B: MASTER optical observation
- GRB 140709B: Swift detection of a burst
- GRB140706A: GROND detection of the Optical/NIR afterglow
- GRB 140705A: KAIT Optical Upper Limit
- GRB 140705A: Swift-XRT refined Analysis
- GRB 140705A: Swift detection of a short burst
- GRB 140703A: P60 observations of a red, slowly-fading afterglow
- Fermi 425667201: optical counterpart search
- GRB 140626A: GROND Afterglow Candidate
- GRB 140622A: iTelescope.Net T11 Optical Observation
- GRB 140622A: KAIT Optical Upper Limit
- GRB 140622A: GROND Upper limits
- GRB 140622A: Swift detection of a short burst
- GRB 140619A: Swift detection of a burst with a possible optical counterpart
- GRB 140614B: Swift detection of a burst
- GRB 140614A: GROND afterglow candidate
- GRB140606B: DCT time of observation correction
- GRB 140606B: Swift XRT refined analysis
- GRB140606B/iPTF14bfu: Discovery Channel Telescope Optical Detection
- Fermi 423717114: Additional P48 and P60 observations
- Fermi423717114: iPTF optical transient candidates
- Konus-Wind observation of GRB 140529A
- GRB 140529A found in ground analysis of BAT slew data
- IPN Triangulation of GRB 140528A
- Swift detection of SFXT IGR J17544-2619
- GRB 140518A: P60 i-/z-band detections
- GRB 140518A: KAIT optical candidate
- GRB 140518A: Swift detection of a burst
- GRB 140515A: KAIT Optical Upper Limit
- Trigger 599041: Swift detection of SFXT IGR J16479-4514
- GRB 140515A: Swift detection of a burst
- GRB 140508A: MITSuME Akeno Optical observation
- GRB 140509B: MAXI/GSC detection
- GRB 140508A: iPTF optical transient candidate
- GRB 140502A: ISON-NM early optical limit
- GRB 140506A: Swift detection of a burst with an optical counterpart
- GRB 140430A: VLT/X-shooter redshift
- GRB140430A: Swift detection of a burst with an optical counterpart
- GRB 140423A: RTT150 optical observations
- IPN Triangulation of GRB 140428B (short/hard)
- GRB 140428A: 1.5m OSN I-band detection
- GRB 140428A: Keck detection of a red optical afterglow candidate
- GRB 140423A: NOT Afterglow Observations
- GRB 140423A pODI/WIYN afterglow photometry
- Swift Trigger 596958 is probably the flare star: DG CVn
- GRB 140423A: Further Observations with Swift/UVOT
- GRB 140423A: KWFC z-band photometry
- GRB 140423A: ISON-MN early photometry and correction to the GCN circ. 16143
- GRB 140423A: Swift/UVOT detection of a possible counterpart
- GRB 140423A: Swift-XRT observations
- GRB 140423A: ROTSE-III Detection of Optical Counterpart
- GRB 140423A optical observations with pODI/WIYN at KPNO
- GRB 140423A: optical afterglow candidate
- GRB 140419A: MITSuME Okayama Optical Observation
- GRB 140419A: Swift detection of a burst with optical afterglow
- Konus-Wind observation of GRB 140413A
- Swift Trigger 595616: a possible GRB
- IPN Triangulation of GRB 140329A
- GRB 140320B: P60 detection of a very red afterglow
- GRB 140320B: Swift-XRT detection of the afterglow