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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

19662 results found.

  1. Swift GRB241026.95: Global MASTER-Net observations report
  2. GRB241025A: 1.3m DFOT optical afterglow detection
  3. GRB 241025A: GROWTH-India Telescope optical observations
  4. GRB 241025A: COLIBRÍ Detection of the Afterglow
  5. GRB 241025A: Swift-XRT refined Analysis
  6. GRB 241025A: Fermi GBM Observation
  7. IPN triangulation of GRB 241022A (short/hard)
  8. LIGO/Virgo/KAGRA S241009l: Upper limits from Swift/BAT-GUANO
  9. GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
  10. EP 241021a: Swift-XRT observations
  11. Swift GRB 241025A: Global MASTER-Net observations report
  12. EP241025a (GRB 241025A): EP observations update
  13. EP 241021A: Swift ToO observations
  14. GRB 241025A: Enhanced Swift-XRT position
  15. GRB 241025A: NOT spectroscopic redshift of z = 4.20
  16. GRB 241025A: DDOTI Afterglow detection
  17. EP241025a (GRB 241025A): EP on-board trigger and autonomous follow-up observation
  18. GRB 241025A: SVOM/GRM observation
  19. GRB 241025A: TRT optical afterglow observation
  20. GRB 241025A: Swift detection of a burst with an optical counterpart
  21. GRB 241018A: EP-FXT afterglow detection
  22. GRB 241018A: Mondy optical upper limit
  23. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  24. GRB 241018A: GROWTH-India telescope optical upper limit
  25. GRB 241018A: Swift-XRT observations
  26. GRB 241018A: NOT optical observations
  27. GRB 241018A: Swift ToO observations
  28. GRB 241006A: VIRT Optical Upper Limit
  29. GRB 240727A: VIRT Optical Upper Limit
  30. GRB 241016B: Fermi GBM Observations
  31. GRB 241017A: Swift-XRT observations
  32. GRB241017a: Liverpool Telescope observations of XRT uncatalogued sources
  33. GRB 241001A: EP-FXT afterglow detection
  34. GRB 241017A: GROWTH-India Telescope optical upper limit
  35. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  36. GRB 241017A: Swift ToO observations
  37. GRB 241010A: Swift-BAT refined analysis
  38. GRB 241013B: Fermi GBM Observation
  39. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  40. GRB 241009A: LCO optical upper limits
  41. GRB 241009A: GRANDMA optical upper limits
  42. GRB 241009A: Swift-XRT afterglow detection
  43. GRB 241010A: JinShan optical observations and potential host galaxy
  44. GRB 241006A: ATCA Radio Upper Limits
  45. GRB 241010A: Swift-XRT refined Analysis
  46. Swift GRB 241010A: Global MASTER-Net observations report
  47. GRB 241010A: J-band observations with WINTER
  48. GRB 241010A: Enhanced Swift-XRT position
  49. GRB 241010A: LCO optical observations
  50. GRB 241010A: Swift detection of a burst with an optical counterpart
  51. GRB 241006A: Swift-BAT refined analysis
  52. GRB 241009A: Swift ToO observations
  53. GRB 241002B: Swift-XRT afterglow detection
  54. GRB 241002A: NOT optical upper limits
  55. GRB 241006A: GRANDMA optical upper limits
  56. GRB 241006A: Swift-XRT refined Analysis
  57. GRB 241006A: PRIME near-infrared upper limits
  58. GRB 241006A: Swift/UVOT Upper Limits
  59. GRB 241006A: SVOM/VT follow-up and optical upper limit
  60. GRB 241001A: Swift-XRT afterglow detection
  61. GRB 241006A: Enhanced Swift-XRT position
  62. GRB 241006A: Swift detection of a burst
  63. Swift GRB241006.91: Global MASTER-Net observations report
  64. GRB 240930B: SVOM/C-GFT optical upper limit
  65. GRB 240930B / EP 240930a: SVOM/GRM observation
  66. GRB 241002B: Fermi GBM Observation
  67. GRB 241002B: Swift-XRT observations
  68. GRB 241002A: Swift-BAT refined analysis
  69. GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
  70. GRB 241002B: Swift ToO observations
  71. GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
  72. GRB 241002C: Swift ToO observations
  73. IPN triangulation of GRB 240930B / EP 240930a
  74. GRB 240930B: CALET Gamma-Ray Burst Monitor detection
  75. GRB 241002A: Swift/UVOT Upper Limits
  76. GRB 241002A: Swift-XRT refined Analysis
  77. GRB 241002A: LCOGT Optical Upper Limits
  78. GRB 241001A: GRANDMA and Kilonova-Catcher optical afterglow detection and upper limits
  79. GRB 241001A: Swift/UVOT Detection
  80. GRB 241001A: Swift-XRT observations
  81. GRB241001A: optical afterglow candidate
  82. GRB 241002A: 1.5m OSN optical upper limit
  83. GRB 241002A: Enhanced Swift-XRT position
  84. GRB 241002A: Swift detection of a burst
  85. GRB 240930B: Fermi GBM Observation
  86. GRB 241001A: Swift ToO observations
  87. GRB 240930B: Swift/BAT-GUANO localization skymap of a burst
  88. SVOM/GRM detection of a burst from SGR Swift J1818.0-1607
  89. AMON NuEM 240926A: Swift XRT Follow-up
  90. Konus-Wind detection of GRB 240912A
  91. Swift Trigger 1256950 is probably not a GRB
  92. LIGO/Virgo/KAGRA S240921cw: Upper limits from Swift/BAT-GUANO
  93. LIGO/Virgo/KAGRA S240920dw: Upper limits from Swift/BAT-GUANO
  94. LIGO/Virgo/KAGRA S240919bn: Upper limits from Swift/BAT-GUANO
  95. GRB 240529A: FRAM-ORM early optical afterglow observations reveal plateau and rebrightening
  96. GW S240915b and S240919bn : Swift UVOT follow-up
  97. Insight-HXMT ToO observations of X-ray bursts from SGR 1E 1841-045 / Kes 73
  98. GRB 240716A: Swift/BAT-GUANO localization skymap of a long burst
  99. LIGO/Virgo S240919bn: GOTO optical upper limits
  100. LIGO/Virgo S240919bn: Swift XRT observations, 10 X-ray sources

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