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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"

6788 results found.

  1. GRB 241030A: Swift-XRT refined Analysis
  2. GRB 241030B: SAO RAS optical observations
  3. Konus-Wind detection of GRB 241030A
  4. GRB 241030A: Fermi-LAT detection
  5. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  6. GRB 241029A: SAO RAS optical observations
  7. EP241021a: SAO RAS observations of rebrightening
  8. GRB 241029A: Swift-XRT observations
  9. GRB 241029A: Fermi GBM Observation
  10. Konus-Wind detection of GRB 241025A
  11. GRB 241025A: further SAO RAS optical observations
  12. GRB 241026A: BTA and Zeiss-1000 optical observations
  13. GRB 241026A Fermi GBM Analysis
  14. GRB 241025A: SAO RAS optical observations
  15. EP241021a: further SAO RAS optical observations
  16. GRB 241026A: Swift-XRT refined Analysis
  17. GRB241025A: 1.3m DFOT optical afterglow detection
  18. ​GRB 241025A: optical photometry from Konkoly
  19. GRB 241025A: Swift-XRT refined Analysis
  20. GRB 241025C: Fermi GBM Detection
  21. GRB 241025A: Fermi GBM Observation
  22. EP 241021a: Swift-XRT observations
  23. EP241025a (GRB 241025A): EP observations update
  24. EP241021a: No Detection in Fermi-GBM Observation
  25. EP241021a: SAO RAS optical observations
  26. EP241021a: 1.3m DFOT Optical observations
  27. EP241021a: Optical upper limits with Kinder observations
  28. EP241021a: TRT optical observations
  29. EP241021a: NOT likely optical counterpart
  30. GRB241017A: 1.3m DFOT optical upper limit
  31. GRB 241018A: 1.3m DFOT Optical upper limit
  32. GRB241018A: XingLong Optical Upper Limit
  33. GRB 241018A: Swift-XRT observations
  34. GRB 241016B: Fermi GBM Observations
  35. GRB 241017A: Swift-XRT observations
  36. GRB 241001A: EP-FXT afterglow detection
  37. GRB 241013B: Fermi GBM Observation
  38. GRB 241013A: Fermi GBM Observation
  39. GRB 241009A: Swift-XRT afterglow detection
  40. GRB 241010A: JinShan optical observations and potential host galaxy
  41. GRB 241010A: Swift-XRT refined Analysis
  42. Fermi-LAT Gamma-ray Observations of IceCube-241006A
  43. GRB 241008A: Fermi GBM Observation
  44. GRB 241008A: Fermi-LAT detection
  45. GRB 241002B: Swift-XRT afterglow detection
  46. Fermi-LAT Gamma-ray Observations of NuEm-240926A
  47. GRB 241006A: Swift-XRT refined Analysis
  48. GRB 241001A: Swift-XRT afterglow detection
  49. GRB 241002B: Fermi GBM Observation
  50. GRB 241002B: Swift-XRT observations
  51. GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
  52. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  53. NuEm-240926A: Upper limits from a search for coincident neutrino events in IceCube
  54. GRB 241002A: Swift-XRT refined Analysis
  55. GRB 241001A: Swift-XRT observations
  56. GRB 240930B: Fermi GBM Observation
  57. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  58. Konus-Wind detection of GRB 240912A
  59. EP240919a / GRB 240919A: SVOM/VT upper limit
  60. LIGO/Virgo S240919bn: Swift XRT observations, 10 X-ray sources
  61. EP240918b and EP240918c: Optical upper limits with Kinder observations
  62. EP240919a: Optical upper limit with Kinder observations
  63. GRB 240919A / EP240919a: SVOM/GRM observation
  64. GRB 240910A: further Swift observations and confirmation of afterglow
  65. EP240918a: Optical upper limits with Kinder observations
  66. GRB 240916A: NOT optical observation
  67. GRB 240916A: Fermi GBM Observation
  68. GRB 240916A: Swift-XRT afterglow detection
  69. LIGO/Virgo S240915b: Swift XRT observations, 8 X-ray sources
  70. EP240913a: VLT/HAWK-I near-infrared upper limits
  71. GRB 240913C: Fermi GBM detection
  72. GRB 240914A: Swift-XRT observations
  73. GRB 240910A: SVOM/VT optical observations
  74. EP240913a: NOT optical upper limits
  75. EP240913a: Swift/XRT detection of an X-ray source within the EP/WXT error circle
  76. GRB 240905E: further NOT optical observations
  77. GRB 240911A: Swift-XRT observations
  78. GRB 240912A: Swift-XRT refined Analysis
  79. GRB 240912A: Fermi GBM Observation
  80. GRB 240910A: Fermi GBM Observation
  81. GRB 240910A: NOT optical observations
  82. GRB 240910A: Swift-XRT detection of GOTO24fvl/AT2024vfp
  83. GRB 240910A: JinShan optical observations
  84. GRB 240825A: 7DT Optical Upper Limit
  85. GRB 240905E: SVOM/VT optical observations
  86. GRB 240910A: SVOM/GRM observation
  87. GRB 240905B: Fermi GBM Observation
  88. EP240908a: TRT optical upper limit
  89. EP240908a: EP detection of a fast X-ray transient
  90. GRB 240905B: Swift-XRT observations
  91. GRB 240905B: Fermi-LAT detection
  92. GRB 240905E: NOT optical upper limits
  93. GRB 240905E: Swift-XRT refined Analysis
  94. GRB 240905E: SAO RAS optical upper limit
  95. GRB 240825A: Swift-BAT refined analysis
  96. GRB 240828A: SAO RAS optical observations
  97. GRB 240828A: Fermi GBM Observation
  98. GRB 240828A: Swift-XRT afterglow detection
  99. GRB 240825A: further SAO RAS optical observations
  100. GRB 240825A: iTelescope optical observations

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