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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"

6094 results found.

  1. GRB 241030A: SAO RAS optical observations
  2. GRB 241030A: Fermi GBM Observation
  3. EP241030a: EP detection of GRB 241030A X-ray Afterglow
  4. GRB241030B: Fermi GBM Observation
  5. GRB 241029A: SVOM/VT optical afterglow observations
  6. EP241021a: Swift-UVOT detection
  7. GRB 241030A: Swift-XRT refined Analysis
  8. GRB 241030B: SAO RAS optical observations
  9. Konus-Wind detection of GRB 241030A
  10. GRB 241030A: Fermi-LAT detection
  11. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  12. GRB 241029A: SAO RAS optical observations
  13. EP241021a: SAO RAS observations of rebrightening
  14. GRB 241029A: Swift-XRT observations
  15. GRB 241029A: Fermi GBM Observation
  16. Konus-Wind detection of GRB 241025A
  17. GRB 241025A: further SAO RAS optical observations
  18. GRB 241026A: BTA and Zeiss-1000 optical observations
  19. GRB 241026A Fermi GBM Analysis
  20. GRB 241025A: SAO RAS optical observations
  21. EP241021a: further SAO RAS optical observations
  22. GRB 241026A: Swift-XRT refined Analysis
  23. GRB241025A: 1.3m DFOT optical afterglow detection
  24. ​GRB 241025A: optical photometry from Konkoly
  25. GRB 241025A: Swift-XRT refined Analysis
  26. GRB 241025C: Fermi GBM Detection
  27. GRB 241025A: Fermi GBM Observation
  28. EP 241021a: Swift-XRT observations
  29. EP241025a (GRB 241025A): EP observations update
  30. EP241021a: No Detection in Fermi-GBM Observation
  31. EP241021a: SAO RAS optical observations
  32. EP241021a: 1.3m DFOT Optical observations
  33. EP241021a: Optical upper limits with Kinder observations
  34. EP241021a: TRT optical observations
  35. EP241021a: NOT likely optical counterpart
  36. GRB241017A: 1.3m DFOT optical upper limit
  37. GRB 241018A: 1.3m DFOT Optical upper limit
  38. GRB241018A: XingLong Optical Upper Limit
  39. GRB 241018A: Swift-XRT observations
  40. GRB 241016B: Fermi GBM Observations
  41. GRB 241017A: Swift-XRT observations
  42. GRB 241001A: EP-FXT afterglow detection
  43. GRB 241013B: Fermi GBM Observation
  44. GRB 241013A: Fermi GBM Observation
  45. GRB 241009A: Swift-XRT afterglow detection
  46. GRB 241010A: JinShan optical observations and potential host galaxy
  47. GRB 241010A: Swift-XRT refined Analysis
  48. Fermi-LAT Gamma-ray Observations of IceCube-241006A
  49. GRB 241008A: Fermi GBM Observation
  50. GRB 241008A: Fermi-LAT detection
  51. GRB 241002B: Swift-XRT afterglow detection
  52. Fermi-LAT Gamma-ray Observations of NuEm-240926A
  53. GRB 241006A: Swift-XRT refined Analysis
  54. GRB 241001A: Swift-XRT afterglow detection
  55. GRB 241002B: Fermi GBM Observation
  56. GRB 241002B: Swift-XRT observations
  57. GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
  58. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  59. NuEm-240926A: Upper limits from a search for coincident neutrino events in IceCube
  60. GRB 241002A: Swift-XRT refined Analysis
  61. GRB 241001A: Swift-XRT observations
  62. GRB 240930B: Fermi GBM Observation
  63. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  64. Konus-Wind detection of GRB 240912A
  65. EP240919a / GRB 240919A: SVOM/VT upper limit
  66. LIGO/Virgo S240919bn: Swift XRT observations, 10 X-ray sources
  67. EP240918b and EP240918c: Optical upper limits with Kinder observations
  68. EP240919a: Optical upper limit with Kinder observations
  69. GRB 240919A / EP240919a: SVOM/GRM observation
  70. GRB 240910A: further Swift observations and confirmation of afterglow
  71. EP240918a: Optical upper limits with Kinder observations
  72. GRB 240916A: NOT optical observation
  73. GRB 240916A: Fermi GBM Observation
  74. GRB 240916A: Swift-XRT afterglow detection
  75. LIGO/Virgo S240915b: Swift XRT observations, 8 X-ray sources
  76. EP240913a: VLT/HAWK-I near-infrared upper limits
  77. GRB 240913C: Fermi GBM detection
  78. GRB 240914A: Swift-XRT observations
  79. GRB 240910A: SVOM/VT optical observations
  80. EP240913a: NOT optical upper limits
  81. EP240913a: Swift/XRT detection of an X-ray source within the EP/WXT error circle
  82. GRB 240905E: further NOT optical observations
  83. GRB 240911A: Swift-XRT observations
  84. GRB 240912A: Swift-XRT refined Analysis
  85. GRB 240912A: Fermi GBM Observation
  86. GRB 240910A: Fermi GBM Observation
  87. GRB 240910A: NOT optical observations
  88. GRB 240910A: Swift-XRT detection of GOTO24fvl/AT2024vfp
  89. GRB 240910A: JinShan optical observations
  90. GRB 240825A: 7DT Optical Upper Limit
  91. GRB 240905E: SVOM/VT optical observations
  92. GRB 240910A: SVOM/GRM observation
  93. GRB 240905B: Fermi GBM Observation
  94. EP240908a: TRT optical upper limit
  95. EP240908a: EP detection of a fast X-ray transient
  96. GRB 240905B: Swift-XRT observations
  97. GRB 240905B: Fermi-LAT detection
  98. GRB 240905E: NOT optical upper limits
  99. GRB 240905E: Swift-XRT refined Analysis
  100. GRB 240905E: SAO RAS optical upper limit

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