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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').
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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"

12170 results found.

  1. Fermi GRB 250916A: Global MASTER-Net observations report
  2. SVOM/sb25091517: SVOM detection of an X-ray transient
  3. GRB 250912A: Swift/BAT-GUANO localization skymap of a possibly short burst
  4. GRB 250912A: Swift-XRT observations
  5. IceCube-Cascade 250911A: Upper limits from a search for additional neutrino events in IceCube
  6. EP250911a: refined analysis of the EP-WXT and EP-FXT observations
  7. EP250911a: Swift-XRT observations
  8. EP250910a: Global MASTER-Net observations report
  9. EP250911a: Einstein Probe detection of an X-ray transient
  10. GRB 250911A: Swift detection of a burst
  11. GRB 250910A / EP250910a: VLT/HAWK-I near-infrared observations
  12. EP250910a/GRB 250910A: EP-WXT detection of a fast X-ray transient
  13. GRB 250909B: AstroSat CZTI detection of a long burst
  14. GRB 250909A: AstroSat CZTI detection
  15. GRB 250910A: SVOM detection of a faint burst
  16. EP#01709240653: Swift-XRT observations
  17. EP250908c: refined analysis of the EP-WXT and EP-FXT observations
  18. EP250908c: Global MASTER-Net observations report
  19. Fermi GRB 250909A: Global MASTER-Net observations report
  20. EP250908c: Einstein Probe detection of an X-ray transient
  21. Fermi-LAT Gamma-ray Observations of IceCube-250905A
  22. GRB 250903A: Swift-XRT afterglow detection
  23. IceCube-250905A: Upper limits from a search for additional neutrino events in IceCube
  24. SVOM/sb25090605: detection of an X-ray transient from the LMXB 4U 0513-40
  25. EP250905b: EP-FXT follow-up observation
  26. EP250905a: Liverpool Telescope observations
  27. EP250905a: refined analysis of the EP-WXT and EP-FXT observations
  28. EP250905b: Global MASTER-Net observations report
  29. EP250905b: EP-WXT detection of a fast X-ray transient
  30. EP250905a: FTW one optical and multiple NIR counterpart candidates
  31. GRB 250905A: Swift-XRT refined Analysis
  32. EP250905a: JinShan likely optical counterpart detection
  33. IceCube-250905A - IceCube observation of a high-energy neutrino candidate track-like event
  34. IceCube Alert 250905.84: Global MASTER-Net observations report
  35. EP250905a: Einstein Probe detection of an X-ray transient
  36. GRB 250903A: Swift/UVOT detection
  37. LIGO/Virgo/KAGRA S250904cv: Updated Sky localization
  38. EP detected a brightening of LMXB 1ES 1735-26.9
  39. GRB 250905A: Swift detection of a burst
  40. Swift GRB250905.09: Global MASTER-Net observations report
  41. GRB 250903A: Swift-XRT observations
  42. EP250903a: Swift-XRT observations
  43. EP#01709201209: Swift-XRT observations
  44. EP250903a: refined analysis of the EP-WXT and EP-FXT observations
  45. GRB 250903A: EP-FXT counterpart detection
  46. EP250901a: Mondy, Assy and SAO RAS optical limits
  47. GRB 250902B: AstroSat CZTI detection
  48. GRB 250903A: SVOM detection of a burst
  49. EP250903a: Einstein Probe detection of an X-ray transient
  50. GRB 250902B: SVOM/GRM observation
  51. Fermi GRB 250902B: Global MASTER-Net observations report
  52. Fermi-LAT Gamma-ray Observations of IceCube-250831A
  53. EP250901a: refined analysis of the EP-WXT and EP-FXT observations
  54. GRB 250901A: EP-FXT follow-up observation
  55. GRB 250901A: SVOM/VT optical afterglow with VHF data
  56. GRB 250901A: Swift-XRT afterglow detection
  57. EP250901a: Swift-XRT observations
  58. EP250827b: Contemporaneous detection of EP X-ray flare EP250827b and ZTF transient ZTF25abmpngy/AT2025wkm
  59. GRB 250901A: SVOM detection of a burst
  60. GRB 250830C: AstroSat CZTI detection of a long burst
  61. EP250901a: Einstein Probe detection of an X-ray transient
  62. EP250831a: EP-FXT follow-up observation
  63. EP250831a: Swift-XRT observations
  64. LIGO/Virgo/KAGRA S250831cc: Coverage and upper limits from MAXI/GSC observations
  65. EP250831a: Global MASTER-Net observations report
  66. EP250831a: EP-WXT detection of a fast X-ray transient
  67. GRB 250831A: Swift-XRT counterpart detection
  68. GRB 250831A: SVOM detection of a soft burst
  69. LIGO/Virgo/KAGRA S250830bp: Coverage and upper limits from MAXI/GSC observations
  70. LIGO/Virgo/KAGRA S250830bp: NED Galaxies in the 4-Update Localization Volume
  71. GRB 250830B: MAXI/GSC detection
  72. GRB 250830A / MAXI J0853+337: MAXI/GSC detection
  73. The EP-WXT trigger 01709200994 is likely a flaring star
  74. LIGO/Virgo/KAGRA S250725j: Observations with the NSF-DOE Vera C. Rubin Observatory
  75. LIGO/Virgo/KAGRA S250818k: MeerKAT detection of an increase in radio flux from AT2025ulz
  76. GRB 250808B: SVOM detection of a burst through offline search
  77. EP250828a: refined analysis of the EP-WXT and EP-FXT observations
  78. EP250828a: Global MASTER-Net observations report
  79. EP250828a: SVOM/VT optical candidate
  80. EP250828a: Seimei/TriCCS optical counterpart detection
  81. EP250828a: Optical upper limit with Kinder observations
  82. EP250828a: Einstein Probe detection of an X-ray transient
  83. EP250827a: Preliminary analysis of the EP-WXT and EP-FXT observations
  84. Fermi GRB 250827A: Global MASTER-Net observations report
  85. EP250827a: Swift-XRT counterpart detection
  86. EP250827a: Einstein Probe detection of an X-ray transient
  87. GRB 250806A: HiPERCAM/GTC limits on a possible supernova
  88. LIGO/Virgo/KAGRA S250818k: SAO RAS BTA z-band observations of AT2025ulz
  89. Fermi GRB 250824B: Global MASTER-Net observations report
  90. GRB 250821B: AstroSat CZTI detection
  91. GRB 250819A: AstroSat CZTI detection
  92. LIGO/Virgo/KAGRA S250818k: FTW Observations Show Continued Reddening of AT 2025ulz
  93. LIGO/Virgo/KAGRA S250818k: Swift Observations of AT 2025ulz - Second Epoch
  94. The EP-WXT trigger 01709200707 is likely a flaring star
  95. The EP-WXT trigger 01709200706 is likely a flaring star
  96. GRB 250823A: Fermi GBM Observation
  97. GRB 250823A: BOOTES6/DPRT early optical detection
  98. GRB 250823A: Swift detection of a burst
  99. GRB 250823A: Fermi GBM Final Real-time Localization
  100. Swift GRB250823.84: Global MASTER-Net observations report

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