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.
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"
6094 results found.
- GRB 240825A: Swift-BAT refined analysis
- GRB 240828A: SAO RAS optical observations
- GRB 240828A: Fermi GBM Observation
- GRB 240828A: Swift-XRT afterglow detection
- GRB 240825A: further SAO RAS optical observations
- GRB 240825A: iTelescope optical observations
- GRB 240828B: Swift-XRT afterglow detection
- GRB 240828A: Fermi-LAT detection
- GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
- GRB 240819A: Swift afterglow confirmation
- Konus-Wind detection of GRB 240825A (bright/long)
- GRB 240825A: Fermi GBM Observation
- GRB 240825A: Swift-XRT refined Analysis
- GRB 240825A: Fermi-LAT detection
- GRB 240824B: Fermi GBM Observation
- GRB 240824B: Swift-XRT afterglow detection
- GRB 240824A: Swift-XRT observations
- GRB 240821A: Swift/UVOT observations of the XRT sources.
- GRB 240821A: Swift-XRT observations
- GECAM-B observation of a short burst from SGR 1E 1841-045 / Kes 73
- GRB 240821A: Fermi GBM Observation
- GRB 240821A: EP-FXT follow-up observation and afterglow candidates
- GRB 240819A: Swift-XRT observations
- EP240820a: EP detection of a fast X-ray transient
- GRB 240819A: X-ray follow-up observation with EP-FXT
- EP240816b: TRT optical upper limit
- EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
- Konus-Wind detection of GRB 240811A
- GRB 240811A: Swift-XRT refined Analysis
- Konus-Wind detection of GRB 240809A
- Konus-Wind detection of GRB 240807A (a counterpart of EP240807a)
- Fermi-LAT gamma-ray observations of IceCube-240808A
- GRB 240809A: GIT afterglow observations
- GRB 240809A: Tentative redshift from NOT
- GRB 240809A: Swift-XRT refined Analysis
- GRB 240809A: JinShan optical observations
- The EP-WXT trigger 01709018832 on August 7th is likely a flaring star
- EP240806a: Gemini North-GMOS spectroscopic redshift of z = 2.818
- EP240804a (GRB 240804B): NOT optical observations
- EP240806a: LCOGT optical counterpart detection
- GRB240805A: Fermi GBM Observation
- Konus-Wind detection of GRB 240804B (a counterpart of EP240804a)
- GRB 240805B: Swift-XRT refined Analysis
- GRB 240805A: Swift-XRT refined Analysis
- GRB 240805A: Fermi-LAT detection
- EP240804a: LCOGT optical counterpart detection
- EP240802a: Time coincidence with GRB 240802A and optical upper limits with Kinder observations
- EP240801a: further SAO RAS optical observations
- EP240801a: SAO RAS optical observations
- EP240801a: follow-up observation with LCOGT
- EP240801a: Kinder follow-up observations of the candidate counterpart
- EP240801a: TRT optical counterpart detection
- GRB 240730A: Swift-XRT refined Analysis
- GRB 240715A: Swift-XRT afterglow detection
- GRB 240730A: Swift detection of a burst
- GRB 240727B: Swift-XRT observations
- GRB 240727A: Swift-XRT refined Analysis
- GRB 240727B: Fermi GBM Observation
- GRB 240727A: TRT optical afterglow detection
- Fermi-LAT gamma-ray observations of IceCube-240725A
- Fermi-LAT gamma-ray observations of IceCube-240721A
- GRB 240720A: Fermi GBM observation
- GRB 240718A: Fermi GBM Observation
- GRB 240718A: Fermi-LAT Detection
- IceCube-Cascade 240714A: X-ray follow-up observation with EP-FXT
- Fermi-LAT gamma-ray observations of IceCube-cascade-240714A
- GRB 240715A: Swift/UVOT observations of the XRT sources.
- GRB 240715A: Swift-XRT observations
- GRB240713A: Swift/UVOT Upper LImits
- GRB 240715A: GECAM-C detection of a short burst
- GRB 240713A: Swift-XRT observations
- GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
- GRB 240712A: Swift-XRT refined Analysis
- GRB 240715A: Fermi GBM Observation
- The EP-WXT source triggered on July 14th is likely a flaring star
- GRB 240713A: NOT optical upper limits on three EP/FXT candidates
- GRB240713A: X-ray follow-up observation with EP-FXT
- GRB 240713B: AstroSat CZTI detection of a long burst
- GRB240713A: Optical upper limit with Kinder observations
- EP240708a: NOT optical observations
- EP240708a: Optical upper limits with Kinder observations
- EP240703c: Kinder optical follow-up and Swift XRT observations
- EP240703a: Kinder optical follow-up observations
- EP240703c: EP-WXT detection of an X-ray transient
- EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
- EP240703a: EP-WXT detection of a fast X-ray transient
- Konus-Wind detection of GRB 240619A
- GRB 240625A: Fermi GBM Observation
- EP240625a: EP-WXT detection of a fast X-ray transient
- GRB240624A: Fermi GBM Observation
- X-ray transient EP240618a: Fermi/GBM non-detection
- EP240618a: Swift/XRT upper limit
- EP240617a: tentative Swift/XRT detection of the afterglow
- GRB 240619A: Swift-XRT probable afterglow detection
- GRB 240619A: Fermi GBM Observation
- LIGO/Virgo S240615dg: Swift XRT observations, 39 X-ray sources
- Fermi trigger No 740430582: Global MASTER-Net observations report
- GRB240615A: 1.3m DFOT optical upper limit
- EP240617a: EP-WXT detection of a fast X-ray transient
- GRB 240615A: Fermi GBM Observation