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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"

18334 results found.

  1. GRB 260914A: EP-FXT follow-up observation
  2. GRB 260915A: SVOM detection of a burst
  3. GRB 260914A: LCO optical observation
  4. GRB 260914A: SVOM/C-GFT optical observations
  5. GRB 260914A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  6. GRB 260914A: SVOM detection of a burst
  7. GRB 260913A: SVOM trigger sb26091302 is not an astrophysical event
  8. GRB 260913A: SVOM/C-GFT optical upper limit
  9. GRB 260913A: SVOM detection of a faint burst
  10. GRB 260909A: OSN 1.5m, CAHA 2.2m and GTC 10.4m optical upper limits
  11. GRB 260907A: SVOM/GRM observation
  12. GRB 260909A: CrAO and AbAO optical upper limits
  13. GRB 260909A: KAIT optical upper limit
  14. GRB 260903A: Swift-XRT observations
  15. GRB 260909A: OHP/T193 z-band upper limit
  16. GRB 260909A: VLT optical and near-infrared upper limits
  17. GRB 260909A: EP-FXT follow-up observation
  18. EP260806a: NOEMA detection
  19. EP260623a: NOEMA detections
  20. GRB 260909A: Mondy optical observations and afterglow candidate
  21. GRB 260909A: Xinglong 2.16m optical upper limit
  22. GRB 260909A: SVOM/C-GFT optical upper limit
  23. GRB 260909A: SVOM detection of a burst
  24. The EP-WXT trigger 01709306297 is likely the known LMXB 4U 1745-203
  25. GRB 260903A: SAO RAS optical upper limit
  26. The EP-WXT trigger 01709305715 is likely a flaring star
  27. EP260903a: EP-FXT follow-up observation
  28. The EP-WXT trigger 01709302592 is likely a flaring star
  29. GRB 260903A: J-band upper limit with WINTER
  30. GRB260903A: Liverpool Telescope optical observations
  31. GRB 260903A: SAO RAS optical observations
  32. EP260903a: EP-WXT detection of a fast X-ray transient
  33. GRB 260830A: Insight-HXMT/HE detection
  34. GRB 260903A: EP-FXT follow-up observation
  35. GRB 260903A: OHP/T193 optical afterglow detection
  36. NuSTAR Transient 260828: SOAR Optical Upper Limits
  37. GRB 260903A: LCO optical counterpart detection
  38. EP260901a: SVOM/VT optical upper limits
  39. EP260901a: EP-FXT follow-up observation
  40. GRB 260829A: SVOM/GRM observation
  41. GRB 260818A: ATCA detection of a candidate radio counterpart
  42. EP260830a: EP-FXT follow-up observation
  43. EP260901a: Global MASTER-Net observations report
  44. GRB 260831B / sb26083106: SVOM/GWAC-F60A/B confirmation of optical variation of nova V* GK Per
  45. NuSTAR Transient 260828: LCO Optical Upper Limits
  46. EP260901a: EP-WXT detection of a fast X-ray transient
  47. GRB 260831B: EP-FXT follow-up observation
  48. GRB 260831B: LCO optical upper limits
  49. EP260830a: EP-WXT detection of a fast X-ray transient
  50. GRB 260827A: SVOM/GRM observation
  51. GRB 260831B: SVOM detection of a possible burst
  52. GRB 260825A: SVOM/GRM observation of a long burst
  53. GRB 260818B: Further EP-FXT observation
  54. GRB 260818B: VLT optical and nIR observations
  55. GRB 260818B: TNG NIR observations
  56. The EP-WXT trigger 01709291839 is likely the known LMXB 4U 1745-203
  57. GRB 260818B: 6 GHz VLA observations
  58. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  59. GRB 260808B: SAO RAS observations of the optical rebrightening
  60. GRB 260822A: PRIME near-infrared upper limits from multiple epochs
  61. GRB 260822A: EP/FXT follow-up observations
  62. GRB 260822A: the candidate optical afterglow is an unrelated type-Ia SN
  63. GRB 260818A: further EP-FXT observations and X-ray afterglow confirmation
  64. EP260822a: EP-FXT non-detection and upper limit
  65. GRB 260822A: SVOM/COLIBRÍ (FM-GFT) possible optical counterpart candidate
  66. EP260822a: Einstein Probe detection of a fast X-ray transient
  67. GRB 260822A: LCO optical upper limits
  68. The EP-WXT trigger 01709287395 is likely a flaring star
  69. GRB 260822A: GROWTH-India Telescope Upper Limits
  70. GRB 260818B: VLA radio observations
  71. GRB 260818B: SVOM/C-GFT optical upper limit
  72. The EP-WXT trigger 01709286204 is likely a flaring star
  73. EP detected a brightening of LMXB 1ES 1735-26.9
  74. GRB 260818B: EP-FXT follow-up observation
  75. GRB 260818A: J-band observations with WINTER
  76. GRB 260818B: NOT optical upper limits
  77. GRB 260810A: SVOM/GRM observation
  78. GRB 260818B: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  79. GRB260818A: EP-FXT follow-up observation
  80. GRB 260818B: LCO optical upper limits
  81. EP260806a: SAO RAS multicolor optical observations
  82. GRB 260818A: LCO optical upper limits
  83. EP260812a: AbAO optical upper limit
  84. GRB 260818A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  85. EP260806a: NUTTELA-TAO optical observations
  86. The EP-WXT trigger 01709281429 is likely a flaring star
  87. EP260812a: AZT-22 optical upper limit
  88. EP260806a: WFST optical observations
  89. The EP-WXT trigger 01709280562 is likely a flaring star
  90. EP260812b: Optical upper limit with Kinder
  91. The EP-WXT trigger 01709279838 is likely a flaring star
  92. GRB 260805D: SVOM/GRM detection of a possible magnetar burst
  93. GRB 260808B: Liverpool Telescope further optical observations
  94. EP260812a: NOT and Liverpool Telescope upper limits:
  95. EP260812b: Liverpool Telescope observations
  96. EP260812a: refined analysis of the EP-WXT and autonomous EP-FXT observation
  97. EP260812a: SVOM/C-GFT optical upper limit
  98. EP260812b: COLIBRÍ optical observations
  99. EP260812b: SVOM/VT optical observation
  100. GRB 260808A: SVOM/GRM observation

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