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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.

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

3328 results found.

  1. EP250207a: EP-WXT detection and XRT follow-up observation
  2. EP-WXT trigger 01709131361: correction to GCN 39214
  3. EP trigger 01709131361 (possible EP250207a): NOT optical observations and flaring star
  4. EP-WXT trigger 01709131361 / LIGO/Virgo/KAGRA S250206dm: FTW optical and NIR observations
  5. Konus-Wind detection of GRB 250204B
  6. LIGO/Virgo/KAGRA S250206dm: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  7. The EP-WXT trigger 01709131347 is likely a flaring star
  8. The EP-WXT trigger 01709131332 is likely a flaring star
  9. The EP-WXT trigger 01709131290 is likely a flaring star
  10. EP250205a/GRB 250205A: correction to the source localization
  11. EP250205a/GRB 250205A: Einstein Probe observation
  12. GRB 250205A: Redshift from OSIRIS+/GTC z = 3.55
  13. GRB 250205A: GOTO optical upper limits
  14. Konus-Wind detection of GRB 250201A
  15. Konus-Wind detection of GRB 250202B
  16. EP 250108A: Upper limits from Fermi-GBM Observations
  17. The EP-WXT trigger 01709131196 is likely a flaring star
  18. The EP-WXT trigger 01709131153 is not a real source
  19. Konus-Wind detection of GRB 250129A
  20. GRB 250127A: EP-FXT second observation epoch and confirmation of the x-ray afterglow fading
  21. Ep250125A: 1.3m DFOT optical upper limit
  22. The EP-WXT trigger 01709131085: KAIT confirmation of the stellar flare
  23. GRB 250127A: CrAO and Terskol optical upper limits
  24. The EP-WXT trigger 01709131085 is likely a flaring star
  25. EP250125a: Upper limits from Swift/BAT-GUANO
  26. GRB 250127A: Swift-XRT observations
  27. GRB 250127A: EP-FXT afterglow detection
  28. EP250125A: Non-detection from Fermi-GBM Observations
  29. EP250108a / SN 2025kg: Refined Analysis of EP-WXT Detection
  30. EP250125a: Optical upper limit with Kinder observations
  31. EP250125a: REM optical counterpart detection
  32. EP250125a: Swift/XRT detection of a fading counterpart
  33. EP250125a: a new X-ray transient detected by Einstein Probe
  34. EP250125a: Gemini-South optical afterglow discovery and redshift z = 2.89
  35. The EP-WXT trigger 01709130758 is a false trigger
  36. The EP-WXT trigger 01709130758 is a false trigger
  37. Konus-Wind detection of a bright burst from SGR 1E1841-045 on 2025 January 23
  38. Konus-Wind detection of GRB 250118B
  39. Konus-Wind detection of GRB 250119B
  40. Konus-Wind detection of GRB 250117A
  41. EP250108a / SN2025kg: Non-detection from ATCA radio follow-up observations
  42. EP 250108A: Late-time optical observation by LCO
  43. EP250108a / SN2025kg: Gemini GMOS-S confirmation of an associated broad-lined SN Ic
  44. EP250108a/AT 2025kg: NOT spectroscopy in agreement with SN Ic-BL
  45. EP250108a / AT 2025kg: the kangaroo is hopping, evidence for optical rebrightening
  46. EP250108a / AT2025kg: GMG Optical Observations
  47. Konus-Wind detection of GRB 250116A
  48. Konus-Wind detection of GRB 250113A
  49. EP250111a: SAO RAS optical upper limit
  50. EP250108a / AT 2025kg: SAO RAS optical observations
  51. EP241021a: SMA radio observation
  52. EP250109b: optical upper limits with the Liverpool Telescope
  53. GRB 250109A / EP250109a: GRBAlpha detection
  54. GRB 250109A / EP250109a: Mephisto optical upper limits
  55. EP250108a: Mephisto detection
  56. EP250108a / AT 2025kg: LCO optical observations
  57. EP250111a: Global MASTER-Net observations report
  58. EP250111a: Swift/XRT detection and fading
  59. EP250108a / AT 2025kg (the "kangaroo”): VLT/X-shooter spectroscopic redshift z = 0.176 and LFBOT classification
  60. EP250108a: optical follow-up observations with the Liverpool Telescope
  61. EP250111a: NOT likely optical counterpart
  62. EP250111a: a new X-ray transient detected by Einstein Probe
  63. EP250108a: further NOT optical observations
  64. GRB 250109A / EP250109a: Swift detection of the X-ray afterglow
  65. Konus-Wind detection of GRB 250107C
  66. EP-WXT trigger EP250108a：Xinglong optical follow-up observations
  67. EP250109a / GRB 250109A: refined EP-WXT analysis and EP-FXT follow-up observation
  68. EP250108a: EP-FXT follow-up observation
  69. GRB 250109A: Fermi GBM Observation
  70. The EP-WXT trigger 01709130111 is likely a flaring star
  71. EP250108a: NOT optical observations
  72. EP-WXT trigger EP250109a：Xinglong optical follow-up observations
  73. GRB 250109a: GMG Optical Upper Limit
  74. EP250109a: Swift/UVOT non-detection
  75. Konus-Wind detection of GRB 250107D (short/hard)
  76. EP250109a: SVOM/VT optical candidate
  77. EP250109a: Global MASTER-Net observations report
  78. EP250109a: GOTO optical upper limits
  79. EP250109a: Swift/XRT non-detection
  80. EP250108a: Global MASTER-Net observations report
  81. EP250109a: EP-WXT detection of an X-ray transient
  82. EP250108a: EP-WXT detection of an X-ray transient
  83. EPWXT01709129925: Xinglong optical observations
  84. The EP-WXT trigger 01709129925 is likely a flaring star
  85. GRB 241229A: SVOM/VT optical upperlimit
  86. EP250101a: Liverpool Telescope optical upper limit
  87. EP241231b: optical upper limit with the Liverpool Telescope
  88. EP250101a: Xinglong optical upper limit
  89. EP241231b and EP250101a: EP-WXT detection of two X-ray transients
  90. GRB 241217a/EP241217b: ATCA Radio Detection
  91. EP241217a: VLA Radio Detection

  92. GRB 241229A: EP-FXT X-ray afterglow confirmation
  93. EP241217A: J band upper limit by SYSU 80cm telescope
  94. GRB 241229A: SAO RAS optical observations
  95. GRB 241229A: Swift-XRT observations
  96. Konus-Wind detection of GRB 241228A
  97. GRB 241229A: EP-FXT afterglow candidates
  98. EP240702a: 7DT Optical upper limits
  99. EP241223a
  100. EP241223a: Global MASTER-Net observations report

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