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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"

28112 results found.

  1. GRB 251201B: SVOM/VT optical fading
  2. Swift GRB 251201B : MASTER optical counterpart detection
  3. GRB 251201B: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at Sutherland Observatory
  4. Swift GRB 251201B: Global MASTER-Net observations report
  5. GRB 251201B: Enhanced Swift-XRT position
  6. EP251118a: Mondy, CrAO, Assy and SAO RAS/Zeiss-1000 optical observations
  7. GRB 251201B: Swift detection of a burst with an optical counterpart
  8. GRB 251201B: Fermi GBM Final Real-time Localization
  9. EP251130a: Mondy optical observations
  10. EP251130a: Optical detections with Kinder observations
  11. SVOM GRB251201.19: Global MASTER-Net observations report
  12. EP251130a: SAO RAS optical observations
  13. EP251130a: GTC OSIRIS+ redshift z = 4.035 and rebrightening
  14. EP251130A: Optical observation from 1.3m DFOT
  15. EP251130a: refined analysis of the EP-WXT and EP-FXT observations
  16. EP251130a: JinShan optical observations
  17. GRB 251201A: MAXI/GSC detection
  18. Fermi GRB 251130B: Global MASTER-Net observations report
  19. GRB 251127A: SVOM/GRM observation
  20. IceCube Alert 251130.75: Global MASTER-Net observations report
  21. EP251130a: Swift-XRT counterpart detection
  22. EP251130a: Global MASTER-Net observations report
  23. EP251130a: COLIBRÍ optical counterpart candidate
  24. EP251130a: Einstein Probe detection of an X-ray transient
  25. GRB 251129A / EP251129a: SAO RAS optical observations
  26. GRB 251126A: SAO RAS optical observations
  27. GRB 251128A: SVOM/GRM observation of a long burst
  28. SVOM GRB 251129A : MASTER optical counterpart detection
  29. GRB 251129A: Swift-XRT afterglow detection
  30. EP251129a: Global MASTER-Net observations report
  31. EP251129a/GRB 251129A : Einstein Probe detection of an X-ray transient
  32. GRB 251129A: SVOM/VT optical counterpart confirmation with VHF data
  33. GRB 251128A: Fermi GBM Observation
  34. GRB 251129A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  35. GRB 251129A: SVOM detection of a burst
  36. SVOM GRB251129A: Global MASTER-Net observations report
  37. GRB 251129A: SVOM detection of a burst
  38. GRB 251126A: Swift-BAT refined analysis
  39. GRB 251126A: TShAO, Mondy, and AbAO optical observations
  40. GRB 251128A: Swift/BAT-GUANO localization skymap of a burst
  41. Fermi GRB 251128A: Global MASTER-Net observations report
  42. GRB 251127A: Glowbug gamma-ray detection
  43. GRB 251126A: OHP/T193 optical observations and tentative spectroscopic redshift
  44. GRB 251126A: further SAO RAS optical observations
  45. GRB 251126A NUTTelA-TAO Early Measurements
  46. LIGO/Virgo/KAGRA S251112cm: GECKO/KMTNet tiling observations and transient candidates
  47. GRB251126A: MAO/AZT-22 optical observations
  48. GRB251126A: Continued optical observation from 1.3m DFOT
  49. GRB 251126A: Swift/UVOT Detection
  50. GRB 251126A: Mondy and SAO RAS optical observations
  51. GRB 251126A: Swift-XRT refined Analysis
  52. GRB 251126A : MITSuME Akeno optical afterglow candidate detection
  53. GRB 251126A: NOT optical observations
  54. GRB 251126A: 1.3m DFOT optical afterglow detection
  55. GRB 251126A: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at McDonald Observatory
  56. GRB 251126A: COLIBRÍ photometric redshift z = 3.5
  57. Fermi GRB 251127A: Global MASTER-Net observations report
  58. GRB 251126A: Enhanced Swift-XRT position
  59. GRB 251126A: Kilonova-Catcher optical afterglow detection
  60. GRB 251126A: Nanshan/HMT optical afterglow detection
  61. Swift GRB 251126A: Global MASTER-Net observations report
  62. GRB 251121A: Fermi GBM Observation
  63. GRB 251126A: GIT discovery of the likely optical afterglow
  64. GRB 251126A: Swift detection of a burst
  65. GRB 251125B: COLIBRÍ further observations and photometric redshift upper limit of z < 3
  66. GRB 251125B: COLIBRÍ observations of fading of the MASTER OT candidate
  67. EP251124b: NOT r- and z-band optical upper limits
  68. Fermi GRB 251125B : MASTER OT J155558.56+581224.1 optical counterpart discovery
  69. Fermi GRB 251125B: Global MASTER-Net observations report
  70. EP251124b: Global MASTER-Net observations report
  71. EP251124b: EP-WXT detection of a fast X-ray transient
  72. EP251124a: Xinglong GWAC-F60A optical observation
  73. Fermi GRB 251125A: Global MASTER-Net observations report
  74. EP251124a: NOT r- and z-band optical upper limits
  75. EP251124a: Global MASTER-Net observations report
  76. EP251124a: Swift-XRT observations
  77. LIGO/Virgo/KAGRA S251112cm: AT 2025adht Kinder follow-up observations
  78. EP251124a: Optical upper limit with Kinder observations
  79. Fermi GRB 251124a: Global MASTER-Net observations report
  80. LIGO/Virgo/KAGRA S251105aj: SVOM/VT optical observations and preliminary results on SVOM J2320.0-2901
  81. LIGO/Virgo/KAGRA S251105aj: EP-FXT follow-up observations and preliminary results on SVOM J2320.0-2901
  82. EP251124a: GROWTH-India Telescope optical upper limits
  83. EP251124a: Einstein Probe detection of an X-ray transient
  84. GRB 251116C: Swift-XRT confirmation of fading
  85. GRB 251122A/EP251122A: 1.3m DFOT optical detection
  86. GRB 251122A / EP251122a: Xinglong 2.16m optical observation
  87. EP251118A: 3.6m DOT optical afterglow detection
  88. GRB 251122A / EP251122a: EP-FXT counterpart detection
  89. EP251122a: refined analysis of the EP-WXT and EP-FXT observations
  90. GRB 251122A / EP251122a: WFST optical observations
  91. GRB 251122A/EP251122a: SVOM/VT optical observations with VHF data
  92. GRB 251122A/EP251122a: Additional, deeper LCO optical r band upper limit
  93. GRB 251122A / EP251122a: LCO optical upper limits
  94. EP251122a / GRB 251122A: optical counterpart candidate with Kinder observations
  95. EP251122a: Global MASTER-Net observations report
  96. GRB 251122A/EP251122a: SVOM/C-GFT upper limit
  97. GRB 251122A / EP251122a: SVOM detection of a long burst
  98. EP251122a: Einstein Probe detection of an X-ray transient
  99. EP251118a: Continued Optical Detection with Kinder observations
  100. LIGO/Virgo/KAGRA S251105aj: SVOM/ECLAIRs detection of a high-energy transient SVOM J2320.0-2901 through targeted search

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