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"24794 results found.
- GRB 170519A: optical observations
- GRB 170519A: Enhanced Swift-XRT position
- GRB 170519A: Swift detection of a burst with an optical counterpart
- LIGO/Virgo G277583: UH88/SNIFS classification of ATLAS and PS1 transients
- GRB 170510A: Swift-XRT afterglow detection
- GRB 170516A: Swift-BAT refined analysis
- GRB 170516A: Swift-XRT refined Analysis
- GRB 170516A: Swift/UVOT Upper Limits
- GRB 170516A: Enhanced Swift-XRT position
- GRB 170516A: Swift detection of a burst
- Swift Trigger AXP CXOU J164710.2-455216: MASTER-OAFA observations
- Swift Trigger on AXP CXOU J164710.2-455216
- GRB 170514A: Fermi GBM detection
- GRB 170510A: Global MASTER Net possible OT observations
- LIGO/Virgo G284239: Konus-Wind observations
- GRB 170510A: LCO possible counterpart
- GRB 170510A: Swift-XRT observations
- GRB 170510A: Fermi GBM observation
- LIGO/Virgo G284239: H.E.S.S. very-high energy gamma-ray follow-up
- LIGO/Virgo G284239: MAXI/GSC observations
- Swift Trigger 752193 is not a GRB
- LIGO/Virgo G284239: AstroSat CZTI upper limits
- GRB 170423A: TAROT Reunion observatory optical observations
- Swift XRT observations of GRB 170424A
- LIGO/Virgo G284239:SVOM/Mini-GWAC observations of the initial skymap
- LIGO/Virgo G284239: HAWC follow-up
- LIGO/Virgo G284239: MASTER automatic follow up and synchronous observations
- LIGO/Virgo G284239: Fermi-LAT search for a high-energy gamma-ray counterpart
- LIGO/Virgo G284239: TZAC TAROT network observations with TRE/TCA/TCH
- LIGO/Virgo: G284239 ANTARES search
- LIGO/Virgo G284239: Swift/BAT data search
- LIGO/Virgo G284239: AGILE GRID observations
- LIGO/Virgo G284239: INTEGRAL search for a prompt gamma-ray counterpart
- LIGO/Virgo G284239: AGILE MCAL Observations
- LIGO/Virgo G284239: IceCube neutrino observations
- GRB 170428A: GTC spectroscopic redshift of candidate host galaxy
- GRB 170428A: TNG optical observations
- GRB 170428A: TAROT La Silla observatory optical observations
- GRB 170428A: RATIR Afterglow Confirmation
- GRB 170428A: GROND detection of the afterglow
- GRB 170428A: Swift/UVOT Upper Limits
- GRB 170428A: Xinglong 2.16-m upper limit and host galaxy candidate
- GRB 170428A: Swift-XRT refined Analysis
- GRB 170428A: Swift-BAT refined analysis
- Swift Trigger 750337 is probably a noise fluctuation
- GRB 170428A: Swift detection of a short burst
- GRB170426.95 MASTER-Net OT detection
- Swift Trigger 750096 is probably a noise fluctuation
- Swift Trigger 750044 is probably a noise fluctuation
- GRB 170424A: LCO Observations
- GRB 170419A: Swift/UVOT Upper Limits
- GRB 170424A: Fermi GBM detection
- GRB 170424A: Fermi-LAT detection
- GRB 170419A: LCO Observations
- GRB 170423A: Fermi GBM detection
- Swift Trigger 748858: AbAO and TSHAO optical observations
- Swift Trigger 748858: TAROT La Silla observatory optical observations
- Swift Trigger 748858: RATIR Optical and NIR Observations
- GRB 170419B, Swift-BAT refined analysis
- GRB 170419B: Zadko observatory - Gingin optical observations
- GRB 170419A: Zadko observatory - Gingin optical observations
- GRB 170419A: Swift-XRT refined Analysis
- GRB 170419B: Fermi GBM observation
- GRB 170419A: Swift-BAT refined analysis
- Swift trigger 748858: Swift BAT, XRT, and UVOT refined analysis
- GRB 170419A: Enhanced Swift-XRT position
- GRB 170419A: Swift detection of a burst
- Swift Trigger 748858: Zadko observatory - Gingin optical observations
- Swift Trigger 748858: a possible GRB
- GRB 170409A: TAROT Reunion observatory optical observations
- GRB 170409A: Fermi GBM Observation
- GRB 170409A: Fermi-LAT detection
- GRB 170405A: SMARTS optical/IR afterglow observations
- GRB 170317A: SAO RAS optical observations
- GRB170405A, Swift-UVOT Detection
- GRB 170405A, Swift-BAT refined analysis
- GRB 170405A: Etelman observatory optical observations
- GRB 170405A: Swift-XRT refined Analysis
- GRB 170405A: RATIR Optical and NIR Observations
- Trigger 745966: Swift detection of 4U1850-03
- GRB 170405A: ISON/Terskol optical observations
- GRB 170405A: Watcher optical detection
- GRB 170405A: Redshift from OSIRIS/GTC
- GRB 170405A: TAROT Reunion observatory optical observations
- GRB 170405A: Enhanced Swift-XRT position
- GRB 170405A: Swift detection of a burst with an optical counterpart
- LIGO/Virgo G275697: Update on significance from offline analyses
- LIGO/Virgo G275404: Update on significance from offline analyses
- LIGO/Virgo G275404: European VLBI Network (EVN) follow-up of the near-IR transient in the AGL J1914+1043 field
- GRB 170325A: optical observations, possible OT/host detection
- Konus-Wind observation of GRB 170403A (short/hard)
- IPN Triangulation of GRB 170403A (short)
- GRB 170403A: Fermi GBM observation
- IceCube-170321A: Konus-Wind upper limits
- Swift Trigger 745090 is a noise trigger near NGC 5195
- Fermi-LAT Gamma-ray Observations of IceCube-170321
- Swift triggered on SAX J1806.5-221
- GRB 170330A: Swift-BAT refined analysis
- GRB 170331A: Swift-BAT refined analysis
- DOAO 1m telescope V, R, I observation of GRB 170317A