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"- GRB 110915A: Deep Near-IR Limits from Magellan
- GRB 110915B: XRT afterglow candidate
- GRB 110903A: Suzaku WAM observation of the prompt emission
- GRB 110915A: Deep Gemini-South i/z-band imaging
- GRB110915A MITSuME Okayama J-band upper-limit
- GRB 110915A: MITSuME Okayama and Ishigakijima Optical upper limits
- GRB 110915A: NOT observations
- GRB 110915A: 1.23m CAHA I-band observations
- GRB 110915B: SuperAGILE localization of a long GRB
- GRB 110915A: Enhanced Swift-XRT position
- GRB 110915A: GMG optical upper limit
- GRB 110915A: MITSuME Akeno Optical upper limits
- GRB 110915A: MASTER-Net early limit
- GRB 110915A: Prompt enhanced Swift-XRT position
- GRB 110915A: Swift detection of a burst
- GRB 110825A: Further Swift/XRT Observations
- GRB 110731A: SAO RAS and Terskol observations
- GRB 110906A(?): Burst detection (unconfirmed) from Swift-BAT slew data
- MAXI J1836-194 (originally GRB 110905A): Swift-BAT refined analysis
- GRB 110905A / X-ray transient MAXI J1836-194: TNT optical observation
- GRB 110905A: Potential BAT trigger on MAXI J1836-194
- GRB 110905A: KAIT observations
- GRB 110905A: Swift detection of a burst
- GRB 110903A: Fermi GBM observation
- GRB 110903A: Swift/UVOT Upper Limits
- GRB 110903A: Swift-XRT observations
- Konus-Wind observation of GRB 110903A
- GRB 110903A: a long GRB detected by INTEGRAL
- GRB 110820A: optical upper limit
- SGR Swift J1834.9-0846: Correction to the Swift-BAT refined spectral analysis
- Trigger 502024: Swift detection of KS 1741-293
- GRB110825A: Fermi GBM observation
- SGR Swift J1834.9-0846: Swift-BAT refined analysis of trigger 501752
- Swift detection of an SGR burst from Swift J1834.9-0846
- GRB 110825A: Suzaku WAM observation of the prompt emission
- GRB 110825A: GMG optical observation
- GRB110825A: ROTSE early time optical limit
- GRB 110827A, Swift-BAT refined analysis
- GRB 110825A: optical afterglow candidate
- GRB 110827A: Swift detection of a burst
- GRB 110825A: field inspection and possible host galaxy
- GRB110825A: Swift target of opportunity observation
- IPN triangulation of GRB110825A (very intense, long-duration)
- GRB 110820A, the review of the sky area in plate archives
- Swift-BAT Trigger 501485 is noise
- Swift-BAT refined analysis of SFXT IGR J08408-4503 (trigger 501368)
- Fermi GBM trigger 110823.518 is not a GRB
- Swift J1834.9-0846: Precise X-ray Position and the Confirmation of its Spin Period
- Konus-Wind observation of GRB 110820B
- GRB 110820A: MASTER-NET first hour observations
- IPN triangulation of GRB 110820B (very long duration, extremely intense)
- GRB 110820A: Swift/UVOT Upper Limits
- GRB 110820A: Position udpate + 2nd epoch data
- GRB 110820A: i-band finding chart + correction to 12295
- GRB 110820A: CQUEAN izY Observation
- GRB 110820A: Swift-XRT refined Analysis
- GRB110820A: MITSuME Ishigakijima Optical Upper Limits
- GRB 110820A: Swift-BAT refined analysis
- GRB 110820A: Enhanced Swift-XRT position
- GRB 110820A: CrAO optical upper limit
- GRB 110820A: MASTER-NET observations
- GRB 110820A: Swift detection of a burst
- GRB 110818A: Fermi GBM observation
- GRB 110818A: Swift/UVOT Upper Limits
- GRB 110818A: Enhanced Swift-XRT position
- GRB 110818A: Optical afterglow and redshift from VLT/X-shooter
- GRB 110818A: Swift-XRT refined Analysis
- GRB 110815A: Swift-XRT and UVOT refined Analysis
- GRB 110818A, Swift-BAT refined analysis
- GRB 110815A : Suzaku WAM observation of the prompt emission
- GRB 110818A: Swift detection of a burst
- Konus-Wind observation of GRB 110815A
- IPN triangulation of GRB110815A (long, intense)
- GRB 110801A: Konus-Wind and Swift/BAT joint spectral analysis
- GRB 110801A: optical observations at Mt. Terskol observatory
- GRB 110812A: SuperAGILE localization of a long GRB.
- Reprocessed enhanced Swift-XRT positions and GRB products: update
- SGR 1834.9-0846/ GRB 110807A, I-band observations
- Konus-Wind observation of GRB 110808B
- Konus-Wind observation of GRB 110808A
- IPN triangulation of GRB 110808B (short/hard/intense)
- A new photometric resource for GRB observers
- RXTE Discovery of the Spin Period of Swift J1834.9-0846
- SGR 1834.9-0846/ GRB 110807A: archival IR observations
- Fermi Gamma-ray Burst Monitor trigger 110809.346 is not a GRB
- GRB 110808A: Swift/UVOT Detection
- Swift Trigger 458942 is probably not a burst
- GRB 110808A: Swift-BAT refined analysis
- GRB 110808A: Swift-XRT refined Analysis
- SGR J1834.9-0846: A Neutron Star in W41?
- Swift SGR 1834.9-0846: Swift-BAT refined analysis
- GRB 110808A: VLT/X-shooter spectroscopy
- GRB 110808A: Enhanced Swift-XRT position
- GRB 110808A: Swift detection of a burst with optical counterpart
- Fermi GBM detection of a SGR-like burst
- GRB 110807A: SAO RAS observations
- GRB 110807A: Swift detection of a burst or a posible new SGR
- Fermi Gamma-ray Burst Monitor trigger 110806.263 is not a GRB
- GRB 110726A: two epochs of SAO RAS optical observations
- Reprocessed enhanced Swift-XRT positions and GRB products