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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"

6791 results found.

  1. GRB241030B: Fermi GBM Observation
  2. GRB 241029A: SVOM/VT optical afterglow observations
  3. EP241021a: Swift-UVOT detection
  4. GRB 241030A: Swift-XRT refined Analysis
  5. GRB 241030B: SAO RAS optical observations
  6. Konus-Wind detection of GRB 241030A
  7. GRB 241030A: Fermi-LAT detection
  8. EP 241021a: further Swift-XRT observations and X-ray counterpart detection
  9. GRB 241029A: SAO RAS optical observations
  10. EP241021a: SAO RAS observations of rebrightening
  11. GRB 241029A: Swift-XRT observations
  12. GRB 241029A: Fermi GBM Observation
  13. Konus-Wind detection of GRB 241025A
  14. GRB 241025A: further SAO RAS optical observations
  15. GRB 241026A: BTA and Zeiss-1000 optical observations
  16. GRB 241026A Fermi GBM Analysis
  17. GRB 241025A: SAO RAS optical observations
  18. EP241021a: further SAO RAS optical observations
  19. GRB 241026A: Swift-XRT refined Analysis
  20. GRB241025A: 1.3m DFOT optical afterglow detection
  21. ​GRB 241025A: optical photometry from Konkoly
  22. GRB 241025A: Swift-XRT refined Analysis
  23. GRB 241025C: Fermi GBM Detection
  24. GRB 241025A: Fermi GBM Observation
  25. EP 241021a: Swift-XRT observations
  26. EP241025a (GRB 241025A): EP observations update
  27. EP241021a: No Detection in Fermi-GBM Observation
  28. EP241021a: SAO RAS optical observations
  29. EP241021a: 1.3m DFOT Optical observations
  30. EP241021a: Optical upper limits with Kinder observations
  31. EP241021a: TRT optical observations
  32. EP241021a: NOT likely optical counterpart
  33. GRB241017A: 1.3m DFOT optical upper limit
  34. GRB 241018A: 1.3m DFOT Optical upper limit
  35. GRB241018A: XingLong Optical Upper Limit
  36. GRB 241018A: Swift-XRT observations
  37. GRB 241016B: Fermi GBM Observations
  38. GRB 241017A: Swift-XRT observations
  39. GRB 241001A: EP-FXT afterglow detection
  40. GRB 241013B: Fermi GBM Observation
  41. GRB 241013A: Fermi GBM Observation
  42. GRB 241009A: Swift-XRT afterglow detection
  43. GRB 241010A: JinShan optical observations and potential host galaxy
  44. GRB 241010A: Swift-XRT refined Analysis
  45. Fermi-LAT Gamma-ray Observations of IceCube-241006A
  46. GRB 241008A: Fermi GBM Observation
  47. GRB 241008A: Fermi-LAT detection
  48. GRB 241002B: Swift-XRT afterglow detection
  49. Fermi-LAT Gamma-ray Observations of NuEm-240926A
  50. GRB 241006A: Swift-XRT refined Analysis
  51. GRB 241001A: Swift-XRT afterglow detection
  52. GRB 241002B: Fermi GBM Observation
  53. GRB 241002B: Swift-XRT observations
  54. GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
  55. GRB 240929A: SAO RAS, Mondy, and CrAO optical observations
  56. NuEm-240926A: Upper limits from a search for coincident neutrino events in IceCube
  57. GRB 241002A: Swift-XRT refined Analysis
  58. GRB 241001A: Swift-XRT observations
  59. GRB 240930B: Fermi GBM Observation
  60. Fermi-LAT Gamma-ray Observations of IceCube-240929A
  61. Konus-Wind detection of GRB 240912A
  62. EP240919a / GRB 240919A: SVOM/VT upper limit
  63. LIGO/Virgo S240919bn: Swift XRT observations, 10 X-ray sources
  64. EP240918b and EP240918c: Optical upper limits with Kinder observations
  65. EP240919a: Optical upper limit with Kinder observations
  66. GRB 240919A / EP240919a: SVOM/GRM observation
  67. GRB 240910A: further Swift observations and confirmation of afterglow
  68. EP240918a: Optical upper limits with Kinder observations
  69. GRB 240916A: NOT optical observation
  70. GRB 240916A: Fermi GBM Observation
  71. GRB 240916A: Swift-XRT afterglow detection
  72. LIGO/Virgo S240915b: Swift XRT observations, 8 X-ray sources
  73. EP240913a: VLT/HAWK-I near-infrared upper limits
  74. GRB 240913C: Fermi GBM detection
  75. GRB 240914A: Swift-XRT observations
  76. GRB 240910A: SVOM/VT optical observations
  77. EP240913a: NOT optical upper limits
  78. EP240913a: Swift/XRT detection of an X-ray source within the EP/WXT error circle
  79. GRB 240905E: further NOT optical observations
  80. GRB 240911A: Swift-XRT observations
  81. GRB 240912A: Swift-XRT refined Analysis
  82. GRB 240912A: Fermi GBM Observation
  83. GRB 240910A: Fermi GBM Observation
  84. GRB 240910A: NOT optical observations
  85. GRB 240910A: Swift-XRT detection of GOTO24fvl/AT2024vfp
  86. GRB 240910A: JinShan optical observations
  87. GRB 240825A: 7DT Optical Upper Limit
  88. GRB 240905E: SVOM/VT optical observations
  89. GRB 240910A: SVOM/GRM observation
  90. GRB 240905B: Fermi GBM Observation
  91. EP240908a: TRT optical upper limit
  92. EP240908a: EP detection of a fast X-ray transient
  93. GRB 240905B: Swift-XRT observations
  94. GRB 240905B: Fermi-LAT detection
  95. GRB 240905E: NOT optical upper limits
  96. GRB 240905E: Swift-XRT refined Analysis
  97. GRB 240905E: SAO RAS optical upper limit
  98. GRB 240825A: Swift-BAT refined analysis
  99. GRB 240828A: SAO RAS optical observations
  100. GRB 240828A: Fermi GBM Observation

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