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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').
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"

65 results found.

  1. IceCube Alert 250330.35: Global MASTER-Net observations report
  2. GRB 250302A: Fermi GBM Observation
  3. EP250308a: Global MASTER-Net observations report
  4. GRB 250216A: AstroSat CZTI detection
  5. GRB 240822A: AstroSat CZTI detection of a short burst
  6. Fermi trigger No 725592555: Global MASTER-Net observations report
  7. GRB 231125A (short): Glowbug gamma-ray detection
  8. Fermi GRB 231106A: Global MASTER-Net observations report
  9. Fermi GRB 231030B: Global MASTER-Net observations report
  10. IceCube Alert 230914.22: Global MASTER-Net observations report
  11. GRB 230728A: Swift/UVOT Upper Limits
  12. GRB 230510B: Fermi GBM detection
  13. GRB 230328B NUTTelA-TAO / BSTI Early Measurements
  14. GRB 221126A: Fermi GBM observation
  15. Konus-Wind detection of a burst from SGR 1935+2154 on 2022 May 25
  16. Fermi GRB 220330A: Global MASTER-Net observations report
  17. Fermi trigger No 652927551: Global MASTER-Net observations report
  18. Fermi GBM observation of a bright burst in the direction of SGR 1935+2154
  19. GRB 210217A: Liverpool Telescope First Hour Observations
  20. GRB 210212A: Swift-XRT refined Analysis
  21. GRB 201221A: Konus-Wind detection and joint Konus-Wind + Swift-BAT spectral analysis
  22. Fermi trigger No 627198169: Global MASTER-Net observations report
  23. Fermi trigger No 606840801: Global MASTER-Net observations report
  24. GRB 200324A: Swift detection of a burst
  25. Fermi trigger No 603949983: Global MASTER-Net observations report
  26. GRB 190919B: GROND detection of the NIR afterglow
  27. GRB 190530A: Swift/UVOT Detection
  28. LIGO/Virgo S190412m: Identification of a GW binary merger candidate
  29. GRB 190114B: Swift/UVOT Upper Limits
  30. GRB 181023A: Swift/UVOT Upper Limits
  31. GRB 180930A: Swift/UVOT Upper Limits
  32. GRB 180620A: Swift/UVOT Detection
  33. GRB 180602A: Swift/UVOT Upper Limits
  34. Trigger 809217: Swift trigger on RS CVn Star HD 8357
  35. GRB 171209A: Swift detection of a burst
  36. GRB 171123A: Swift/UVOT Upper Limits
  37. GRB 170728B: Swift/UVOT Further Analysis
  38. GRB 160227A: Swift/UVOT Detection
  39. GRB 160225A: Swift/UVOT Upper Limits
  40. GRB 151228B: Swift-XRT refined Analysis
  41. Konus-Wind observation of GRB 150430A
  42. GRB 150323C: additional optical observations in Mondy
  43. GRB 141022A: Swift/UVOT Upper Limits
  44. GRB 140219A: Fermi GBM Detection
  45. GRB 140102A: Swift/UVOT Detection
  46. GRB 121123A: NIKA (New IRAM KID Arrays) millimetre observations at the 30-m Pico Veleta telescope
  47. GRB 120521C: Swift/UVOT Upper Limits
  48. GRB 110905A / MAXI J1836-194: optical monitoring
  49. Trigger 504307: Swift detection of MAXI J1836-194
  50. MAXI J1836-194 (originally GRB 110905A): Swift-BAT refined analysis
  51. GRB 110905A / X-ray transient MAXI J1836-194: TNT optical observation
  52. GRB 110905A: Potential BAT trigger on MAXI J1836-194
  53. Konus-Wind observation of GRB 100423A
  54. Tentative redshift of GRB100413A from X-ray data
  55. GRB 100302A: Optical observations at Crni Vrh
  56. GRB090809: Swift/UVOT observations
  57. GRB 090530B: Fermi GBM detection
  58. GRB 090515: Swift/UVOT Observations
  59. GRB 080723A: Swift/UVOT Upper Limits
  60. Swift Trigger 315630: Swift/UVOT Upper Limits
  61. GRB071118 MITSuME OAO optical observation
  62. GRB070721A: Swift/UVOT Detection of a Weak Afterglow
  63. GRB060428B: possible detection of an optical counterpart by Swift/UVOT.
  64. GRB 060413: Swift detection of a burst
  65. GRB 050721A: Early Swift XRT analysis results

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