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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"

26054 results found.

  1. GRB 241026A: J-band observations with WINTER
  2. GRB 241025A: SAO RAS optical observations
  3. GRB 241026A: Las Cumbres optical detection
  4. GRB 241025A: Mondy optical observations
  5. GRB 241026A: Swift-XRT refined Analysis
  6. GRB 241026A: Enhanced Swift-XRT position
  7. GRB 241026A: KAIT optical observations
  8. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  9. GRB 241026A: SAO RAS observations of possible optical afterglow
  10. GRB 241026A: Prompt enhanced Swift-XRT position
  11. GRB 241026A: Swift detection of a burst
  12. Swift GRB241026.95: Global MASTER-Net observations report
  13. GRB241025A: 1.3m DFOT optical afterglow detection
  14. ​GRB 241025A: optical photometry from Konkoly
  15. GRB 241025A: GROWTH-India Telescope optical observations
  16. GRB 241025A: COLIBRÍ Detection of the Afterglow
  17. GRB 241025A: Swift-XRT refined Analysis
  18. GRB 241025A: Fermi GBM Observation
  19. IPN triangulation of GRB 241022A (short/hard)
  20. LIGO/Virgo/KAGRA S241009l: Upper limits from Swift/BAT-GUANO
  21. GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
  22. EP 241021a: Swift-XRT observations
  23. Swift GRB 241025A: Global MASTER-Net observations report
  24. EP241025a (GRB 241025A): EP observations update
  25. GRB 241025A : SVOM/VT optical afterglow observations
  26. EP 241021A: Swift ToO observations
  27. GRB 241025A: Enhanced Swift-XRT position
  28. GRB 241025A: NOT spectroscopic redshift of z = 4.20
  29. GRB 241025A: DDOTI Afterglow detection
  30. EP241025a (GRB 241025A): EP on-board trigger and autonomous follow-up observation
  31. GRB 241025A: SVOM/GRM observation
  32. GRB 241025A: TRT optical afterglow observation
  33. GRB 241025A: Swift detection of a burst with an optical counterpart
  34. GRB 241001A: ATCA radio observations
  35. GRB 241010A: VIRT Optical Upper Limit
  36. EP241021a: VLT/FORS2 redshift z = 0.75
  37. EP241021a: KAIT optical observations
  38. EP241021a: EP-FXT follow-up observation update
  39. GRB241017A: 1.3m DFOT optical upper limit
  40. GRB 241018A: 1.3m DFOT Optical upper limit
  41. GRB 241018A: EP-FXT afterglow detection
  42. GRB 241018A: BOOTES-4/MET optical upper limit
  43. GRB 241018A: Mondy optical upper limit
  44. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  45. GRB 241018A: GROWTH-India telescope optical upper limit
  46. GRB 241018A: Swift-XRT observations
  47. GRB 241018A: REM optical/NIR upper limits
  48. GRB 241018A: NOT optical observations
  49. GRB 241018A: LCO/0.4m optical upper limits
  50. GRB 241018A: Swift ToO observations
  51. GRB 241006A: VIRT Optical Upper Limit
  52. GRB 240727A: VIRT Optical Upper Limit
  53. GRB 241018A: X-ray afterglow candidate observed by MXT
  54. GRB 241016B: Fermi GBM Observations
  55. GRB 241017A: Swift-XRT observations
  56. GRB241017a: Liverpool Telescope observations of XRT uncatalogued sources
  57. GRB 241001A: EP-FXT afterglow detection
  58. GRB 241017A: GROWTH-India Telescope optical upper limit
  59. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  60. GRB 241017A: Swift ToO observations
  61. GRB 241010A: Swift-BAT refined analysis
  62. GRB 241013B: Fermi GBM Observation
  63. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  64. GRB 241009A: LCO optical upper limits
  65. GRB 241009A: GRANDMA optical upper limits
  66. GRB 241009A: Swift-XRT afterglow detection
  67. GRB 241010A: JinShan optical observations and potential host galaxy
  68. GRB 241006A: ATCA Radio Upper Limits
  69. GRB 241010A: Swift-XRT refined Analysis
  70. Swift GRB 241010A: Global MASTER-Net observations report
  71. GRB 241010A: J-band observations with WINTER
  72. GRB 241010A: Enhanced Swift-XRT position
  73. GRB 241010A: LCO optical observations
  74. GRB 241010A: Swift detection of a burst with an optical counterpart
  75. GRB 241006A: Swift-BAT refined analysis
  76. GRB 241009A: Swift ToO observations
  77. GRB 241002B: Swift-XRT afterglow detection
  78. GRB 241002A: NOT optical upper limits
  79. GRB 241006A: GRANDMA optical upper limits
  80. GRB 240910A: LBT optical observations
  81. GRB 241006A: Swift-XRT refined Analysis
  82. GRB 241006A: PRIME near-infrared upper limits
  83. GRB 241006A: Swift/UVOT Upper Limits
  84. GRB 241006A: SVOM/VT follow-up and optical upper limit
  85. GRB 241001A: Swift-XRT afterglow detection
  86. GRB 241006A: Enhanced Swift-XRT position
  87. GRB 241006A: Swift detection of a burst
  88. Swift GRB241006.91: Global MASTER-Net observations report
  89. GRB 240930B: SVOM/C-GFT optical upper limit
  90. GRB 240930B / EP 240930a: SVOM/GRM observation
  91. GRB 241002B: Fermi GBM Observation
  92. GRB 241002B: Swift-XRT observations
  93. GRB 241002A: Swift-BAT refined analysis
  94. GRB 241002B: Swift/BAT-GUANO localization skymap of a burst
  95. GRB 241002B: Swift ToO observations
  96. GRB 241002C: Swift-XRT observations confirm the source to be EI Eri
  97. GRB 241002C: Swift ToO observations
  98. IPN triangulation of GRB 240930B / EP 240930a
  99. GRB 240930B: CALET Gamma-Ray Burst Monitor detection
  100. GRB 241002C: X-ray afterglow candidate observed by SVOM/MXT

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