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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"

19122 results found.

  1. GRB 241026A: Swift-BAT refined analysis
  2. GRB 241030A: SVOM/C-GFT optical observations
  3. GRB 241030A: Multiband optical detection with Mephisto
  4. GRB 241030A: SVOM/VT optical afterglow observations
  5. GRB 241025A: The discovery of a BdHN I from data of Swift, Fermi, SVOM and Einstein Probe telescopes
  6. GRB 241030A : MITSuME Akeno optical afterglow detection
  7. GRB 241030A: Enhanced Swift-XRT position
  8. GRB 241030A: TRT optical observations
  9. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  10. GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart
  11. GRB 241030A: Swift detection of a burst with a bright optical counterpart
  12. GRB 241026A: Swift/UVOT Upper Limits
  13. GRB 241029A: Swift-XRT observations
  14. GRB 241029A: Swift ToO observations
  15. GRB 241026A: the 100th GRB detected by GRBAlpha
  16. Konus-Wind detection of GRB 241025A
  17. GRB 241026A: GECAM detection
  18. GRB 241026A: SVOM/GRM observation
  19. GRB 241025A: Swift/UVOT Detection
  20. GRB 241026A: GROWTH-India Telescope optical observations
  21. GRB 241026A Fermi GBM Analysis
  22. GRB 241026A: J-band observations with WINTER
  23. GRB 241025A: SAO RAS optical observations
  24. GRB 241026A: Las Cumbres optical detection
  25. GRB 241025A: Mondy optical observations
  26. GRB 241026A: Swift-XRT refined Analysis
  27. GRB 241026A: Enhanced Swift-XRT position
  28. GRB 241026A: KAIT optical observations
  29. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  30. GRB 241026A: SAO RAS observations of possible optical afterglow
  31. GRB 241026A: Prompt enhanced Swift-XRT position
  32. GRB 241026A: Swift detection of a burst
  33. Swift GRB241026.95: Global MASTER-Net observations report
  34. GRB241025A: 1.3m DFOT optical afterglow detection
  35. GRB 241025A: GROWTH-India Telescope optical observations
  36. GRB 241025A: COLIBRÍ Detection of the Afterglow
  37. GRB 241025A: Swift-XRT refined Analysis
  38. GRB 241025A: Fermi GBM Observation
  39. IPN triangulation of GRB 241022A (short/hard)
  40. LIGO/Virgo/KAGRA S241009l: Upper limits from Swift/BAT-GUANO
  41. GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
  42. EP 241021a: Swift-XRT observations
  43. Swift GRB 241025A: Global MASTER-Net observations report
  44. EP241025a (GRB 241025A): EP observations update
  45. EP 241021A: Swift ToO observations
  46. GRB 241025A: Enhanced Swift-XRT position
  47. GRB 241025A: NOT spectroscopic redshift of z = 4.20
  48. GRB 241025A: DDOTI Afterglow detection
  49. EP241025a (GRB 241025A): EP on-board trigger and autonomous follow-up observation
  50. GRB 241025A: SVOM/GRM observation
  51. GRB 241025A: TRT optical afterglow observation
  52. GRB 241025A: Swift detection of a burst with an optical counterpart
  53. GRB 241018A: EP-FXT afterglow detection
  54. GRB 241018A: Mondy optical upper limit
  55. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  56. GRB 241018A: GROWTH-India telescope optical upper limit
  57. GRB 241018A: Swift-XRT observations
  58. GRB 241018A: NOT optical observations
  59. GRB 241018A: Swift ToO observations
  60. GRB 241006A: VIRT Optical Upper Limit
  61. GRB 240727A: VIRT Optical Upper Limit
  62. GRB 241016B: Fermi GBM Observations
  63. GRB 241017A: Swift-XRT observations
  64. GRB241017a: Liverpool Telescope observations of XRT uncatalogued sources
  65. GRB 241001A: EP-FXT afterglow detection
  66. GRB 241017A: GROWTH-India Telescope optical upper limit
  67. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  68. GRB 241017A: Swift ToO observations
  69. GRB 241010A: Swift-BAT refined analysis
  70. GRB 241013B: Fermi GBM Observation
  71. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  72. GRB 241009A: LCO optical upper limits
  73. GRB 241009A: GRANDMA optical upper limits
  74. GRB 241009A: Swift-XRT afterglow detection
  75. GRB 241010A: JinShan optical observations and potential host galaxy
  76. GRB 241006A: ATCA Radio Upper Limits
  77. GRB 241010A: Swift-XRT refined Analysis
  78. Swift GRB 241010A: Global MASTER-Net observations report
  79. GRB 241010A: J-band observations with WINTER
  80. GRB 241010A: Enhanced Swift-XRT position
  81. GRB 241010A: LCO optical observations
  82. GRB 241010A: Swift detection of a burst with an optical counterpart
  83. GRB 241006A: Swift-BAT refined analysis
  84. GRB 241009A: Swift ToO observations
  85. GRB 241002B: Swift-XRT afterglow detection
  86. GRB 241002A: NOT optical upper limits
  87. GRB 241006A: GRANDMA optical upper limits
  88. GRB 241006A: Swift-XRT refined Analysis
  89. GRB 241006A: PRIME near-infrared upper limits
  90. GRB 241006A: Swift/UVOT Upper Limits
  91. GRB 241006A: SVOM/VT follow-up and optical upper limit
  92. GRB 241001A: Swift-XRT afterglow detection
  93. GRB 241006A: Enhanced Swift-XRT position
  94. GRB 241006A: Swift detection of a burst
  95. Swift GRB241006.91: Global MASTER-Net observations report
  96. GRB 240930B: SVOM/C-GFT optical upper limit
  97. GRB 240930B / EP 240930a: SVOM/GRM observation
  98. GRB 241002B: Fermi GBM Observation
  99. GRB 241002B: Swift-XRT observations
  100. GRB 241002A: Swift-BAT refined analysis

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