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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.

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

16218 results found.

  1. GRB 241030B : GIT optical upper limits
  2. GRB 241030B: LCOGT Optical Upper Limits
  3. GRB 241030B: Swift-BAT refined analysis
  4. GRB 241029A: COLIBRI Detection of the Optical Counterpart
  5. GRB 241030B: Swift/UVOT Detection
  6. GRB 241029A: LCO optical detection
  7. GRB 241030B: GTC/OSIRIS+ tentative spectroscopic redshift z = 2.82
  8. GRB 241030B : MITSuME Akeno optical upper limits
  9. GRB 241030A: COLIBRI Continuing Detection of the Afterglow
  10. GRB 241030B: SVOM/VT optical afterglow observations
  11. GRB 241030B: COLIBRÍ Upper Limits on the Optical Counterpart
  12. EP241030a: EP detection of GRB 241030A X-ray Afterglow
  13. GRB 241030B: BTA observations
  14. GRB 241029A: SVOM/VT optical afterglow observations
  15. GRB 241030B: Enhanced Swift-XRT position
  16. GRB241030B: GRANDMA/TAROT Upper Limit
  17. GRB 241030A: Swift-XRT refined Analysis
  18. GRB 241030B: SAO RAS optical observations
  19. GRB 241030B: AKO Optical Afterglow Detection
  20. GRB 241030B: Nanshan/HMT optical afterglow detection
  21. GRB 241030B: Swift detection of a burst
  22. GRB 240912A: radio detection with the VLA
  23. GRB 241030A: AKO Optical Afterglow Detection
  24. GRB 241030A: Swift/UVOT Detection
  25. GRB 241030A: SVOM/C-GFT optical observations
  26. GRB 241026A: LBT optical observations
  27. EP241021a: Optical rebrightening observations with Mephisto
  28. EP241026b: EP-FXT follow-up observation
  29. GRB 241030A: Multiband optical detection with Mephisto
  30. GRB 241030A: SVOM/VT optical afterglow observations
  31. GRB 241030A : MITSuME Akeno optical afterglow detection
  32. GRB 241030A: Enhanced Swift-XRT position
  33. GRB 241029A: GROWTH-India Telescope optical follow up
  34. GRB 241030A: ULL-ASTRO-MASTER detection of a bright optical counterpart with the LCOGT 40-cm telescope at McDonald Observatory
  35. GRB 241030A: COLIBRÍ Detection of the Bright Optical Counterpart
  36. GRB 241030A: Swift detection of a burst with a bright optical counterpart
  37. GRB 241029A: SAO RAS optical observations
  38. GRB 241026A: SAO RAS optical observations
  39. EP240919a / GRB 240919A: ATCA Detection of Radio Counterpart
  40. EP241021a: SAO RAS observations of rebrightening
  41. GRB 241029A: GTC/OSIRIS+ spectroscopic redshift z=1.072
  42. EP241021a: ATCA radio observations
  43. MISTRAL@OHP photometric and spectroscopic observations of GRB 241029A
  44. GRB 241026A: Swift/UVOT Upper Limits
  45. GRB 241029A: AKO Optical Afterglow Detection
  46. EP241021a: continued SOAR observations confirm optical rebrightening
  47. GRB 241029A: Xinglong-2.16m optical afterglow confirmation
  48. GRB 241029A: Mephisto observations
  49. EP 241026b: LBT possible optical counterpart (brightening source)
  50. GRB 241029A: TRT optical afterglow candidate detection
  51. GRB 241026A: TNOT optical counterpart detection
  52. GRB 241025A (EP241025a): Optical afterglow observations with the Tsinghua-Nanshan Optical Telescope
  53. GRB 241025A: further SAO RAS optical observations
  54. GRB 241026A: BTA and Zeiss-1000 optical observations
  55. GRB 241026A: SVOM/GRM observation
  56. EP241026B: GROWTH-India Telescope optical upper limit
  57. GRB 241025A: Swift/UVOT Detection
  58. GRB 241026A: GROWTH-India Telescope optical observations
  59. GRB 241026A: J-band observations with WINTER
  60. GRB 241025A: SAO RAS optical observations
  61. GRB 241026A: Las Cumbres optical detection
  62. GRB 241025A: Mondy optical observations
  63. EP241021a: SOAR observations of the optical counterpart
  64. EP241021a: further SAO RAS optical observations
  65. EP241026a (GRB 241026A): EP on-board trigger and follow-up observation
  66. GRB 241026A: Swift-XRT refined Analysis
  67. EP 241026b: LBT optical observations
  68. GRB 241026A: Enhanced Swift-XRT position
  69. EP241026b: EP detection of a fast X-ray transient
  70. GRB 241026A: COLIBRÍ Detection of the Optical Counterpart
  71. GRB 241026A: SAO RAS observations of possible optical afterglow
  72. GRB 241026A: Swift detection of a burst
  73. GRB241025A: 1.3m DFOT optical afterglow detection
  74. EP241021a: optical follow-up observations with Xinglong Observatory
  75. GRB 241025A: GROWTH-India Telescope optical observations
  76. GRB 241025A: COLIBRÍ Detection of the Afterglow
  77. IPN triangulation of GRB 241022A (short/hard)
  78. EP241025a (GRB 241025A): EP observations update
  79. GRB 241025A : SVOM/VT optical afterglow observations
  80. EP241021a: Liverpool Telescope optical follow-up observations
  81. GRB 241025A: Enhanced Swift-XRT position
  82. GRB 241025A: DDOTI Afterglow detection
  83. EP241025a (GRB 241025A): EP on-board trigger and autonomous follow-up observation
  84. GRB 241025A: TRT optical afterglow observation
  85. GRB 241025A: Swift detection of a burst with an optical counterpart
  86. EP241021a: GTC OSIRIS+ spectroscopy of the optical counterpart
  87. GRB 241001A: ATCA radio observations
  88. GRB 241010A: VIRT Optical Upper Limit
  89. EP241021a: SAO RAS optical observations
  90. EP241021a: KAIT optical observations
  91. EP241021a: EP-FXT follow-up observation update
  92. EP241021a: 1.3m DFOT Optical observations
  93. EP241021a: Optical upper limits with Kinder observations
  94. EP241021a: TRT optical observations
  95. GRB 241018A: SVOM/C-GFT optical observations
  96. EP241021a: NOT likely optical counterpart
  97. GRB241017A: 1.3m DFOT optical upper limit
  98. GRB 241018A: 1.3m DFOT Optical upper limit
  99. GRB 241018A: EP-FXT afterglow detection
  100. EP241021a: GOTO optical upper limits

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