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"7447 results found.
- GRB 180721A: Swift detection of a burst
- GRB 180720C: Swift detection of a burst or possible Galactic Transient
- GRB 180720B: LCO Haleakala possible bright optical candidate
- Swift detects a flare from AX 1631.9-4752
- GRB 180718A: Swift ToO observations
- GRB 180718B: Swift ToO observations
- GRB 180715A: LCO Sutherland possible optical candidate
- GRB 180703A: optical afterglow confirmation
- GRB 180709A: Swift detection of a burst
- Trigger 846740: Swift trigger near NGC5055
- GRB 180706A: Swift detection of a burst with optical counterpart
- GRB 180703A: LCO Sutherland possible optical candidate
- GRB 180703A: Tiled Swift observations
- GRB 180630A: Swift detection of a burst with an optical counterpart
- GRB 180626A: Swift detection of a burst with an optical counterpart
- GRB 180624A: GROND observations
- GRB 180624A: LCO Siding Springs afterglow candidate
- GRB 180624A: Swift detection of a burst
- GRB 180623A: Swift detection of a burst
- GRB 180620B: Swift detection of a burst with an optical counterpart
- GRB 180620A: ISON-MN afterglow confirmation
- GRB 180620A: Swift detection of a burst with an optical counterpart
- GRB 180618A: Swift detection of a burst with an optical counterpart
- GRB 180614A: Swift detection of a burst
- GRB 180613A: Swift detection of a burst
- GRB 180602A: Swift detection of a burst
- Swift Trigger 834937 is not a GRB
- GRB 180514A: CrAO/ZTSH optical observations and afterglow candidate
- GRB 180514A: Swift detection of a burst
- GRB 180510B: Swift detection of a burst with an optical counterpart
- GRB 180510A: Swift detection of a burst
- Chandra observations of GW170817 reveal a fading afterglow
- Chandra observations of GW170817 260 days since merger: first statistically significant evidence for an X-ray decay
- GRB 180504A: ePESSTO NTT NIR observations
- GRB 180504A: NOT afterglow candidate
- GRB 180504A: Swift detection of a burst
- GRB 180425A: Swift detection of a burst
- LIGO/Virgo G299232: LOFAR follow-up
- GRB 180418A: KAIT Optical Afterglow Candidate
- GRB 180410A: Swift detection of a burst or a Galactic transient.
- GRB 180409A: Tiled Swift observations
- GRB 180404B: Swift detection of a burst with an optical counterpart
- GRB 180404A: Swift detection of a burst with an optical afterglow
- GRB 180402A: KAIT Optical Upper Limit
- GRB 180402A: Swift detection of a possibly short burst
- GRB 180331B: Swift detection of a burst
- GRB 180331A: Swift detection of a burst
- GRB 180329B: Swift detection of a burst with an optical afterglow
- GRB 180325A: Swift detection of a burst with an optical counterpart
- GRB 180324A: KAIT Optical Upper Limit
- GRB 180324A: Swift detection of a burst
- GRB 180316A: Swift detection of a burst
- GRB 180314B: Swift detection of a burst
- GRB 180314A: TAROT La Silla observatory optical observations
- GRB 180314A: Swift detection of a burst with an optical counterpart
- GRB 180311A: Swift detection of a burst
- GRB 180305A: Mondy optical observations
- GRB 180305A: RATIR Optical Afterglow Candidate
- GRB 180305A: Swift ToO observations
- Swift Trigger 811686 is probably not an astrophysical source.
- GRB 180224A: Swift detection of a burst with an optical counterpart
- GRB 180222A: Swift detection of a burst
- Swift trigger 811074 (possible GRB 180221A): Swift refined analysis
- GRB 180210A: Tiled Swift observations
- GRB 180210A: Swift ToO observations
- Trigger 809374: Swift detection of a possible non-burst faint source
- GRB 180205A: Swift detection of a burst with a bright optical counterpart
- GRB 180204A: Swift detection of a short burst
- GW170817/GRB170817A: Updated results from the full Chandra dataset
- LIGO/Virgo GW170817: Chandra X-ray Emission Continues to Rise ~156 Days Post-Merger
- GRB 180115A: MITSuME Akeno optical upper limits
- GRB 180113A: Swift ToO observations
- GRB 180115A: Swift detection of a burst with an optical counterpart.
- GRB 180113A: KAIT Optical Observations
- GRB 180111A: Swift detection of a burst with an optical counterpart
- GRB 180103A: Swift ToO observations
- GRB 180102A: Swift detection of a burst
- IceCube-171106A: Konus-Wind upper limits
- IceCube-171015A: Konus-Wind upper limits
- IceCube-170922A: Konus-Wind upper limits
- GRB 171222A: Swift detection of a burst
- GRB 171216A: Swift detection of a burst
- GRB 171212A: Swift detection of a burst or a Galactic transient
- GRB 171210A: Swift-XRT and UVOT observations
- GRB 171210A: Swift ToO observations
- GRB 171209A: Enhanced Swift-XRT position
- Swift Trigger 796115 is probably not a GRB
- GRB 171209A: LCO 1-m telescope observations
- GRB 171209A: Swift detection of a burst
- LIGO/Virgo G298048: Brightening X-ray Emission from GW170817/GRB170817A/SSS17a
- LIGO/Virgo GW170817: Chandra X-ray brightening of the counterpart 108 days since merger
- GRB 171205A: Swift detection of a burst
- Pan-STARRS follow-up of IceCube-171106A
- LIGO/Virgo G299232: LOFAR follow-up
- GRB 171124A: Swift ToO observations
- GRB 171123A: Swift detection of a burst
- GRB 171120A: Swift detection of a burst
- GRB 171115A: Swift detection of a burst
- LIGO/Virgo G288732/GW170608: updated localization from parameter estimation
- INTEGRAL observation of IceCube-171106A