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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"

43885 results found.

  1. EP250827b: Gemini Spectroscopic Confirmation of AT2025wkm as a Ic-BL Supernova
  2. GRB 250904A: Swift detection of a burst
  3. GRB 250902A: CALET Gamma-Ray Burst Monitor detection
  4. LIGO/Virgo/KAGRA S250904ae: Updated Sky localization
  5. GRB 250902A: VZLUSAT-2 detection
  6. LIGO/Virgo/KAGRA S250904cv: Identification of a GW compact binary merger candidate
  7. GRB 250903A: Swift-XRT observations
  8. EP250903a: Swift-XRT observations
  9. EP#01709201209: Swift-XRT observations
  10. EP250903a: retraction of the LCO candidate, and discovery of the likely counterpart
  11. EP-WXT trigger 01709201209: Liverpool Telescope upper limits
  12. GRB 250830C: VZLUSAT-2 detection
  13. EP250903a: refined analysis of the EP-WXT and EP-FXT observations
  14. LIGO/Virgo/KAGRA S250904br: Identification of a GW compact binary merger candidate
  15. GRB 250903A: VLT X-shooter spectroscopic redshift z = 1.590
  16. The EP-WXT trigger 01709201209 is likely a flaring star
  17. LIGO/Virgo/KAGRA S250904ae: Identification of a GW compact binary merger candidate
  18. GRB 250903A: EP-FXT counterpart detection
  19. GRB 250902A: GECAM-B detection
  20. GRB 250903A: LCO optical observation
  21. GRB 250903A: LCO optical afterglow detection
  22. GRB 250903A: SVOM/VT optical confirmation with VHF data
  23. EP250903a: SVOM/VT optical confirmation
  24. EP250901a: Mondy, Assy and SAO RAS optical limits
  25. Subject GRB 250903A: SVOM/MXT afterglow detection
  26. EP250903a: LCO candidate counterpart discovery
  27. GRB 250903A: TRT optical counterpart detection
  28. GRB 250902B: AstroSat CZTI detection
  29. GRB 250903A: SVOM detection of a burst
  30. EP250903a: Global MASTER-Net observations report
  31. EP250903a: TRT optical observations
  32. EP250903a: Einstein Probe detection of an X-ray transient
  33. EP 250827B: Detection of supernova counterpart by LCO.
  34. EP/WXT01709201159: GOTO optical follow-up
  35. EP250827b / AT 2025wkm: TRT optical observations
  36. EP250827b: NOT spectroscopic observations and AT 2025wkm classification as a broad-lined type-Ic supernova
  37. EP250827b: continued Liverpool Telescope observations
  38. GRB 250902B: SVOM/GRM observation
  39. EP250827b: SVOM/VT observation of AT 2025wkm
  40. LIGO/VIRGO/KAGRA S250818k: No evidence for radio variability of AT2025ulz in MeerKAT 3 GHz data
  41. GRB 250831A (SVOM trigger sb25083102): KAIT confirmation of stellar flare
  42. Fermi GRB 250902B: Global MASTER-Net observations report
  43. Fermi-LAT Gamma-ray Observations of IceCube-250831A
  44. GRB 250902A: Fermi GBM Detection
  45. GRB 250902B: Fermi GBM Final Real-time Localization
  46. IceCube-250831A: Upper limits from a search for additional neutrino events in IceCube
  47. GRB 250830B: Swift-XRT afterglow detection
  48. LIGO/Virgo/KAGRA S250902av: 1 counterpart neutrino candidate event from an IceCube neutrino search
  49. LIGO/Virgo/KAGRA S250901cb: Updated Sky localization
  50. EP250827b: Liverpool Telescope observations
  51. GRB 250831A (SVOM trigger sb25083102): confirmation of a stellar flare by SVOM/VT
  52. GRB 250902A: SVOM/GRM observation
  53. EP250828a: Early near-infrared follow-up with MIRAGE on the MDM 1.3m telescope
  54. EP250901a: refined analysis of the EP-WXT and EP-FXT observations
  55. GRB 250901A: EP-FXT follow-up observation
  56. GRB 250901A: NOT optical observations
  57. GRB 250902A: Fermi GBM Final Real-time Localization
  58. IceCube-Cascade 250828A: Upper limits from a search for additional neutrino events in IceCube
  59. GRB 250901A: SVOM/VT optical afterglow with VHF data
  60. GRB 250901A: Swift-XRT afterglow detection
  61. EP250901a: Swift-XRT observations
  62. LIGO/Virgo/KAGRA S250830bp: DECam GW-MMADS candidates
  63. GRB 250901A: LCO optical upper limit
  64. EP250827b: Swift observations of AT 2025wkm
  65. LIGO/Virgo/KAGRA S250830bp: DECam DESGW Epoch 1 Candidates
  66. EP250827b: Gemini Spectroscopy of AT 2025wkm
  67. LIGO/Virgo/KAGRA S250901cb: Identification of a GW compact binary merger candidate
  68. EP250831a: NOT optical observations and tentative afterglow candidate
  69. EP250827b: FTW Observations of AT 2025wkm
  70. EP250827b: Contemporaneous detection of EP X-ray flare EP250827b and ZTF transient ZTF25abmpngy/AT2025wkm
  71. GRB 250901A: SVOM detection of a burst
  72. GRB 250831B: SVOM/GRM observation
  73. GRB 250830C: Insight-HXMT detection
  74. EP250901a: Mephisto optical upper limits
  75. GRB 250830C: GECAM-B detection
  76. EP250901a: Global MASTER-Net observations report
  77. GRB 250830C: AstroSat CZTI detection of a long burst
  78. EP250901a: Einstein Probe detection of an X-ray transient
  79. LIGO/Virgo/KAGRA S250830m: Updated Sky localization
  80. EP250831a: EP-FXT follow-up observation
  81. EP250831a: Swift-XRT observations
  82. LIGO/Virgo/KAGRA S250831cc: Coverage and upper limits from MAXI/GSC observations
  83. IceCube Alert 250831.75: Global MASTER-Net observations report
  84. EP250831a: Global MASTER-Net observations report
  85. IceCube-250831A - IceCube observation of a high-energy neutrino candidate track-like event
  86. EP250831a: EP-WXT detection of a fast X-ray transient
  87. GRB 250831A (SVOM trigger sb25083102) is likely an outburst from star G 272-61
  88. GRB 250831A: Swift-XRT counterpart detection
  89. GRB 250831A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  90. GRB 250831A: SVOM/VT upper limit with VHF data
  91. GRB 250831A: SVOM detection of a soft burst
  92. GRB 250830B: Swift-XRT observations
  93. EP250830a: Global MASTER-Net observations report
  94. EP250830a/GRB 250830B: Einstein Probe detection of an X-ray transient and Swift/XRT follow-up
  95. LIGO/Virgo/KAGRA S250830bp: Coverage and upper limits from MAXI/GSC observations
  96. LIGO/Virgo/KAGRA S250830bp GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  97. LIGO/Virgo/KAGRA S250830bp: NED Galaxies in the 4-Update Localization Volume
  98. LIGO/Virgo/KAGRA S250830bp: Updated Sky localization, EM Bright Classification, and Source Classification
  99. LIGO/Virgo/KAGRA S250830bp: Identification of a GW compact binary merger candidate
  100. EP-WXT trigger 01709200994: Liverpool Telescope upper limits

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