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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').
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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.

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subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

32179 results found.

  1. GRB 241026A: KAIT optical observations
  2. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  3. GRB 241026A: SAO RAS observations of possible optical afterglow
  4. Fermi GRB 241026A: Global MASTER-Net observations report
  5. GRB 241026A: Prompt enhanced Swift-XRT position
  6. GRB 241026A: Swift detection of a burst
  7. GRB 241026A: Fermi GBM Final Real-time Localization
  8. GRB241025A: 1.3m DFOT optical afterglow detection
  9. ​GRB 241025A: optical photometry from Konkoly
  10. GRB 241025A: GROWTH-India Telescope optical observations
  11. GRB 241025A: COLIBRÍ Detection of the Afterglow
  12. GRB 241025A: Swift-XRT refined Analysis
  13. GRB 241025C: Fermi GBM Detection
  14. GRB 241025A: Fermi GBM Observation
  15. IPN triangulation of GRB 241022A (short/hard)
  16. LIGO/Virgo/KAGRA S241009l: Upper limits from Swift/BAT-GUANO
  17. GRB 241025C: Fermi GBM Final Localization
  18. GRB 241025A: GRANDMA and Kilonova-Catcher optical afterglow detections and upperlimits
  19. GRB 241025B: Fermi GBM Final Localization
  20. EP 241021a: Swift-XRT observations
  21. Fermi GRB 241025A: Global MASTER-Net observations report
  22. Swift GRB 241025A: Global MASTER-Net observations report
  23. EP241025a (GRB 241025A): EP observations update
  24. GRB 241025A : SVOM/VT optical afterglow observations
  25. GRB 241025A: Enhanced Swift-XRT position
  26. GRB 241001A: JWST spectroscopic identification of a supernova counterpart
  27. GRB 241025A: NOT spectroscopic redshift of z = 4.20
  28. GRB 241025A: DDOTI Afterglow detection
  29. EP241025a (GRB 241025A): EP on-board trigger and autonomous follow-up observation
  30. GRB 241025A: SVOM/GRM observation
  31. GRB 241025A: TRT optical afterglow observation
  32. Fermi GRB 241024B: Global MASTER-Net observations report
  33. GRB 241025A: Fermi GBM Final Real-time Localization
  34. GRB 241025A: Swift detection of a burst with an optical counterpart
  35. GRB 241001A: ATCA radio observations
  36. GRB 241024B: Fermi GBM Final Localization
  37. EP241021a: No Detection in Fermi-GBM Observation
  38. GRB 241010A: VIRT Optical Upper Limit
  39. GRB 241024A: Fermi GBM Final Localisation
  40. EP241021a: VLT/FORS2 redshift z = 0.75
  41. EP241021a: SAO RAS optical observations
  42. EP241021a: KAIT optical observations
  43. IPN triangulation of GRB 241021A (long)
  44. GRB 241018A: SVOM/C-GFT optical observations
  45. GRB241017A: 1.3m DFOT optical upper limit
  46. GRB 241018A: 1.3m DFOT Optical upper limit
  47. GRB 241018A: EP-FXT afterglow detection
  48. Konus-Wind detection of GRB 241018A
  49. GRB 241018A: SVOM/GRM observation
  50. GRB 241018A/sb24101802: Mephisto optical upper limit
  51. GRB 241017A/sb24101702: Mephisto optical upper limit
  52. GRB 241018A: BOOTES-4/MET optical upper limit
  53. GRB 241018A: Mondy optical upper limit
  54. GRB 241018A: SVOM/VT further analysis and counterpart confirmed
  55. GRB 241018A: GROWTH-India telescope optical upper limit
  56. GRB 241018A: Swift-XRT observations
  57. GRB 241018A: REM optical/NIR upper limits
  58. GRB 241018A: NOT optical observations
  59. GRB 241017A: SVOM/VT follow-up and optical upper limit
  60. GRB 241018A: SVOM/VT follow-up and optical candidate
  61. GRB 241018A: LCO/0.4m optical upper limits
  62. GRB 241018A: Swift ToO observations
  63. GRB 241006A: VIRT Optical Upper Limit
  64. GRB 240727A: VIRT Optical Upper Limit
  65. GRB 241018A: X-ray afterglow candidate observed by MXT
  66. GRB 241016B: Fermi GBM Observations
  67. GRB 241018A: Detection of a bright long GRB by SVOM
  68. GRB 241017A: Swift-XRT observations
  69. GRB 241001A: EP-FXT afterglow detection
  70. GRB 241017A: GROWTH-India Telescope optical upper limit
  71. GRB 241016B: Swift/BAT-GUANO localization skymap of a short burst
  72. GRB 241017A: J-band upper limit from WINTER
  73. GRB 241016B: SVOM/GRM observation
  74. GRB241016C: Fermi GBM Final Localization
  75. Fermi Gamma-ray Burst Monitor trigger 750792698/241016730 is not a GRB
  76. GRB 241017A: Swift ToO observations
  77. GRB 241017A : Detection of a weak and soft long duration GRB by SVOM/ECLAIRs
  78. Fermi GRB 241016B: Global MASTER-Net observations report
  79. GRB 241016B: Fermi GBM Final Localization
  80. Fermi GRB 241016A: Global MASTER-Net observations report
  81. GRB 241016A: Fermi GBM Final Real-time Localization
  82. GRB 241010A: Swift-BAT refined analysis
  83. GRB 241013B: Fermi GBM Observation
  84. GRB 241013B: Swift/BAT-GUANO localization skymap of a burst
  85. GRB 241013A: Fermi GBM Observation
  86. GRB 240916A: radio detection with the VLA
  87. GRB241013A: REM observations
  88. GRB 241009A: LCO optical upper limits
  89. GRB 241013B: SVOM/GRM observation
  90. Fermi GRB 241013B: Global MASTER-Net observations report
  91. GRB 241013B: Fermi GBM Final Real-time Localization
  92. GRB 241013A: a long GRB detected by INTEGRAL
  93. GRB 241013A: Fermi GBM Final Real-time Localization
  94. Fermi Gamma-ray Burst Monitor GRB trigger 750372658/241011869 (GRB 241011A) is not a GRB
  95. GRB 241011A: Fermi GBM Final Real-time Localization
  96. GRB 241009A: GRANDMA optical upper limits
  97. GRB 241009A: Swift-XRT afterglow detection
  98. GRB 241010A: JinShan optical observations and potential host galaxy
  99. GRB 241006A: ATCA Radio Upper Limits
  100. GRB 241010A: Swift-XRT refined Analysis

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