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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"

42517 results found.

  1. Fermi-LAT Gamma-ray Observations of IceCube-250831A
  2. GRB 250902A: Fermi GBM Detection
  3. GRB 250901A: Swift/UVOT Upper Limit
  4. GRB 250902B: Fermi GBM Final Real-time Localization
  5. IceCube-250831A: Upper limits from a search for additional neutrino events in IceCube
  6. GRB 250830B: Swift-XRT afterglow detection
  7. LIGO/Virgo/KAGRA S250902av: 1 counterpart neutrino candidate event from an IceCube neutrino search
  8. EP250827b: Liverpool Telescope observations
  9. GRB 250831A (SVOM trigger sb25083102): confirmation of a stellar flare by SVOM/VT
  10. GRB 250902A: SVOM/GRM observation
  11. EP250828a: Early near-infrared follow-up with MIRAGE on the MDM 1.3m telescope
  12. EP250901a: refined analysis of the EP-WXT and EP-FXT observations
  13. GRB 250901A: EP-FXT follow-up observation
  14. GRB 250901A: NOT optical observations
  15. GRB 250902A: Fermi GBM Final Real-time Localization
  16. IceCube-Cascade 250828A: Upper limits from a search for additional neutrino events in IceCube
  17. GRB 250901A: SVOM/VT optical afterglow with VHF data
  18. GRB 250901A: Swift-XRT afterglow detection
  19. EP250901a: Swift-XRT observations
  20. GRB 250901A: LCO optical upper limit
  21. EP250827b: Swift observations of AT 2025wkm
  22. LIGO/Virgo/KAGRA S250830bp: DECam DESGW Epoch 1 Candidates
  23. EP250827b: Gemini Spectroscopy of AT 2025wkm
  24. LIGO/Virgo/KAGRA S250901cb: Identification of a GW compact binary merger candidate
  25. EP250831a: NOT optical observations and tentative afterglow candidate
  26. EP250827b: FTW Observations of AT 2025wkm
  27. EP250827b: Contemporaneous detection of EP X-ray flare EP250827b and ZTF transient ZTF25abmpngy/AT2025wkm
  28. GRB 250901A: SVOM detection of a burst
  29. GRB 250831B: SVOM/GRM observation
  30. GRB 250830C: Insight-HXMT detection
  31. EP250901a: Mephisto optical upper limits
  32. GRB 250830C: GECAM-B detection
  33. EP250901a: Global MASTER-Net observations report
  34. GRB 250830C: AstroSat CZTI detection of a long burst
  35. EP250901a: Einstein Probe detection of an X-ray transient
  36. EP250831a: EP-FXT follow-up observation
  37. EP250831a: Swift-XRT observations
  38. LIGO/Virgo/KAGRA S250831cc: Coverage and upper limits from MAXI/GSC observations
  39. IceCube Alert 250831.75: Global MASTER-Net observations report
  40. EP250831a: Global MASTER-Net observations report
  41. IceCube-250831A - IceCube observation of a high-energy neutrino candidate track-like event
  42. EP250831a: EP-WXT detection of a fast X-ray transient
  43. GRB 250831A (SVOM trigger sb25083102) is likely an outburst from star G 272-61
  44. GRB 250831A: Swift-XRT counterpart detection
  45. GRB 250831A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  46. GRB 250831A: SVOM/VT upper limit with VHF data
  47. GRB 250831A: SVOM detection of a soft burst
  48. GRB 250830B: Swift-XRT observations
  49. EP250830a: Global MASTER-Net observations report
  50. EP250830a/GRB 250830B: Einstein Probe detection of an X-ray transient and Swift/XRT follow-up
  51. LIGO/Virgo/KAGRA S250830bp: Coverage and upper limits from MAXI/GSC observations
  52. LIGO/Virgo/KAGRA S250830bp GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  53. LIGO/Virgo/KAGRA S250830bp: NED Galaxies in the 4-Update Localization Volume
  54. LIGO/Virgo/KAGRA S250830bp: Updated Sky localization, EM Bright Classification, and Source Classification
  55. LIGO/Virgo/KAGRA S250830bp: Identification of a GW compact binary merger candidate
  56. EP-WXT trigger 01709200994: Liverpool Telescope upper limits
  57. GRB 250830B: Swift ToO observations
  58. GRB 250830B: MAXI/GSC detection
  59. LIGO/Virgo/KAGRA S250830m: Identification of a GW compact binary merger candidate
  60. GRB 250830A / MAXI J0853+337: MAXI/GSC detection
  61. The EP-WXT trigger 01709200994 is likely a flaring star
  62. GRB 250828B: Swift-BAT refined analysis
  63. EP250821a: SOAR observations
  64. EP250827a: very early ATLAS detections, starting 43 sec after the EP trigger
  65. LIGO/Virgo/KAGRA S250725j: Observations with the NSF-DOE Vera C. Rubin Observatory
  66. LIGO/Virgo/KAGRA S250818k: MeerKAT detection of an increase in radio flux from AT2025ulz
  67. GRB 250808B: SVOM detection of a burst through offline search
  68. EP250828a: refined analysis of the EP-WXT and EP-FXT observations
  69. EP250828a: Optical counterpart detection with Kinder observations
  70. EP250828a: Liverpool Telescope upper limits
  71. Swift GRB 250828B: Global MASTER-Net observations report
  72. EP250828a: Global MASTER-Net observations report
  73. EP-WXT trigger 01709200800 : KAIT optical observations
  74. EP250828a: KAIT optical upper limit
  75. EP250827a: Swift/UVOT Detection
  76. EP250828a: NOT optical counterpart confirmation
  77. EP250828a: SVOM/VT optical candidate
  78. EP250828a: Seimei/TriCCS optical counterpart detection
  79. GRB 250828B: Swift detection of a burst
  80. EP250827a: STEP/T80S Confirmation of fading optical counterpart
  81. EP250828a: Optical upper limit with Kinder observations
  82. LIGO/Virgo/KAGRA S250818k: uGMRT 1.3 GHz observations of AT2025ulz
  83. EP250827a: LCO observations show fading optical counterpart
  84. GRB 250828A: Fermi GBM Final Localization
  85. EP250828a: Einstein Probe detection of an X-ray transient
  86. EP250827a: Preliminary analysis of the EP-WXT and EP-FXT observations
  87. GRID detection of GRB 250824A
  88. LIGO/Virgo/KAGRA S250827fo: Identification of a GW compact binary merger candidate
  89. EP250827A: VLT/X-shooter redshift confirmation
  90. Fermi GRB 250827A: Global MASTER-Net observations report
  91. EP250827a: confirmation of optical rebrightening with LCO
  92. EP250827a: GOTO observation of the optical afterglow
  93. GRB 250826A: SVOM/GRM observation
  94. GRB 250827A: Fermi GBM Final Real-time Localization
  95. EP250827A: An optical rebrightening was detected by LCO.
  96. EP250827a: Swift-XRT counterpart detection
  97. The EP-WXT trigger 01709200800 is likely a flaring star
  98. EP250827a: TRT optical observations
  99. EP250827a: BOOTES-7 early optical dectection
  100. EP250827a / GRB 250827A: MASTER-OAFA OT observation

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