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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"

74 results found.

  1. EP260321a: Global MASTER-Net observations report
  2. GRB 260223A: SVOM/GRM observation
  3. GRB 251230A: Swift-XRT refined Analysis
  4. EP251222a: Global MASTER-Net observations report
  5. Fermi GRB 251127A: Global MASTER-Net observations report
  6. Swift GRB 251018A: Global MASTER-Net observations report
  7. GRB 250901A: SVOM detection of a burst
  8. GRB 250821B: AstroSat CZTI detection
  9. GRB 250521D: SVOM/GRM analysis suggests a possible “long” duration type I burst
  10. IceCube Alert 250330.35: Global MASTER-Net observations report
  11. GRB 250302A: Fermi GBM Observation
  12. EP250308a: Global MASTER-Net observations report
  13. GRB 250216A: AstroSat CZTI detection
  14. GRB 240822A: AstroSat CZTI detection of a short burst
  15. Fermi trigger No 725592555: Global MASTER-Net observations report
  16. GRB 231125A (short): Glowbug gamma-ray detection
  17. Fermi GRB 231106A: Global MASTER-Net observations report
  18. Fermi GRB 231030B: Global MASTER-Net observations report
  19. IceCube Alert 230914.22: Global MASTER-Net observations report
  20. GRB 230728A: Swift/UVOT Upper Limits
  21. GRB 230510B: Fermi GBM detection
  22. GRB 230328B NUTTelA-TAO / BSTI Early Measurements
  23. GRB 221126A: Fermi GBM observation
  24. Konus-Wind detection of a burst from SGR 1935+2154 on 2022 May 25
  25. Fermi GRB 220330A: Global MASTER-Net observations report
  26. Fermi trigger No 652927551: Global MASTER-Net observations report
  27. Fermi GBM observation of a bright burst in the direction of SGR 1935+2154
  28. GRB 210217A: Liverpool Telescope First Hour Observations
  29. GRB 210212A: Swift-XRT refined Analysis
  30. GRB 201221A: Konus-Wind detection and joint Konus-Wind + Swift-BAT spectral analysis
  31. Fermi trigger No 627198169: Global MASTER-Net observations report
  32. Fermi trigger No 606840801: Global MASTER-Net observations report
  33. GRB 200324A: Swift detection of a burst
  34. Fermi trigger No 603949983: Global MASTER-Net observations report
  35. GRB 190919B: GROND detection of the NIR afterglow
  36. GRB 190530A: Swift/UVOT Detection
  37. LIGO/Virgo S190412m: Identification of a GW binary merger candidate
  38. GRB 190114B: Swift/UVOT Upper Limits
  39. GRB 181023A: Swift/UVOT Upper Limits
  40. GRB 180930A: Swift/UVOT Upper Limits
  41. GRB 180620A: Swift/UVOT Detection
  42. GRB 180602A: Swift/UVOT Upper Limits
  43. Trigger 809217: Swift trigger on RS CVn Star HD 8357
  44. GRB 171209A: Swift detection of a burst
  45. GRB 171123A: Swift/UVOT Upper Limits
  46. GRB 170728B: Swift/UVOT Further Analysis
  47. GRB 160227A: Swift/UVOT Detection
  48. GRB 160225A: Swift/UVOT Upper Limits
  49. GRB 151228B: Swift-XRT refined Analysis
  50. Konus-Wind observation of GRB 150430A
  51. GRB 150323C: additional optical observations in Mondy
  52. GRB 141022A: Swift/UVOT Upper Limits
  53. GRB 140219A: Fermi GBM Detection
  54. GRB 140102A: Swift/UVOT Detection
  55. GRB 121123A: NIKA (New IRAM KID Arrays) millimetre observations at the 30-m Pico Veleta telescope
  56. GRB 120521C: Swift/UVOT Upper Limits
  57. GRB 110905A / MAXI J1836-194: optical monitoring
  58. Trigger 504307: Swift detection of MAXI J1836-194
  59. MAXI J1836-194 (originally GRB 110905A): Swift-BAT refined analysis
  60. GRB 110905A / X-ray transient MAXI J1836-194: TNT optical observation
  61. GRB 110905A: Potential BAT trigger on MAXI J1836-194
  62. Konus-Wind observation of GRB 100423A
  63. Tentative redshift of GRB100413A from X-ray data
  64. GRB 100302A: Optical observations at Crni Vrh
  65. GRB090809: Swift/UVOT observations
  66. GRB 090530B: Fermi GBM detection
  67. GRB 090515: Swift/UVOT Observations
  68. GRB 080723A: Swift/UVOT Upper Limits
  69. Swift Trigger 315630: Swift/UVOT Upper Limits
  70. GRB071118 MITSuME OAO optical observation
  71. GRB070721A: Swift/UVOT Detection of a Weak Afterglow
  72. GRB060428B: possible detection of an optical counterpart by Swift/UVOT.
  73. GRB 060413: Swift detection of a burst
  74. GRB 050721A: Early Swift XRT analysis results

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