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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"

32571 results found.

  1. EP250908c: refined analysis of the EP-WXT and EP-FXT observations
  2. GRB 250907A: CALET Gamma-Ray Burst Monitor detection
  3. EP250908c: SVOM/VT optical observation
  4. EP250908c: VLT/FORS2 optical counterpart identification
  5. EP250908b: SVOM/VT optical candidate (Coordinate supplement for GCN 41758)
  6. EP250908b: SVOM/VT optical candidate
  7. EP250908c: Global MASTER-Net observations report
  8. Fermi GRB 250909A: Global MASTER-Net observations report
  9. LIGO/Virgo/KAGRA S250908y: Identification of a GW compact binary merger candidate
  10. GRB 250905A: Swift-BAT refined analysis
  11. Fermi-LAT Gamma-ray Observations of IceCube-250905A
  12. GRB 250903A: Swift-XRT afterglow detection
  13. LIGO/Virgo/KAGRA S250906ca: Identification of a GW compact binary merger candidate
  14. IceCube-250905A: Upper limits from a search for additional neutrino events in IceCube
  15. EP250905a: Liverpool Telescope i-band upper limits
  16. LIGO/Virgo/KAGRA S250830bp: DECam/SOAR GW-MMADS updates
  17. EP250905b: EP-FXT follow-up observation
  18. LIGO/Virgo/KAGRA S250830bp: DECam DESGW Epoch 2 Candidates
  19. EP250905a: Liverpool Telescope observations
  20. EP250905a: refined analysis of the EP-WXT and EP-FXT observations
  21. EP250905b: Global MASTER-Net observations report
  22. EP250905a: FTW one optical and multiple NIR counterpart candidates
  23. EP250905a: JinShan likely optical counterpart detection
  24. GRB 250904A: Swift-BAT refined analysis
  25. GRB 250905A: Swift/UVOT Upper Limits
  26. EP250905a: Global MASTER-Net observations report
  27. GRB 250901A - SVOM/ECLAIRs refined analysis
  28. GRB250904A: Liverpool Telescope upper limits
  29. GRB 250904A: Swift/UVOT Detection
  30. GRB 250903A: Swift/UVOT detection
  31. LIGO/Virgo/KAGRA S250904cv: Updated Sky localization
  32. LIGO/Virgo/KAGRA S250904br: Updated Sky localization
  33. GRB 250905A: KAIT optical upper limit
  34. Swift GRB 250904A: Global MASTER-Net observations report
  35. GRB 250904A: TRT optical counterpart detection
  36. EP250827a and EP250827b: Upper limit from Fermi-GBM Observations
  37. GRB 250902B: CALET Gamma-Ray Burst Monitor detection
  38. EP250827b: Gemini Spectroscopic Confirmation of AT2025wkm as a Ic-BL Supernova
  39. GRB 250902A: CALET Gamma-Ray Burst Monitor detection
  40. LIGO/Virgo/KAGRA S250904ae: Updated Sky localization
  41. GRB 250902A: VZLUSAT-2 detection
  42. LIGO/Virgo/KAGRA S250904cv: Identification of a GW compact binary merger candidate
  43. GRB 250903A: Swift-XRT observations
  44. EP250903a: Swift-XRT observations
  45. EP#01709201209: Swift-XRT observations
  46. EP250903a: retraction of the LCO candidate, and discovery of the likely counterpart
  47. EP-WXT trigger 01709201209: Liverpool Telescope upper limits
  48. GRB 250830C: VZLUSAT-2 detection
  49. EP250903a: refined analysis of the EP-WXT and EP-FXT observations
  50. LIGO/Virgo/KAGRA S250904br: Identification of a GW compact binary merger candidate
  51. GRB 250903A: VLT X-shooter spectroscopic redshift z = 1.590
  52. LIGO/Virgo/KAGRA S250904ae: Identification of a GW compact binary merger candidate
  53. GRB 250903A: EP-FXT counterpart detection
  54. GRB 250902A: GECAM-B detection
  55. GRB 250903A: LCO optical observation
  56. GRB 250903A: LCO optical afterglow detection
  57. GRB 250903A: SVOM/VT optical confirmation with VHF data
  58. EP250903a: SVOM/VT optical confirmation
  59. EP250901a: Mondy, Assy and SAO RAS optical limits
  60. Subject GRB 250903A: SVOM/MXT afterglow detection
  61. EP250903a: LCO candidate counterpart discovery
  62. GRB 250903A: TRT optical counterpart detection
  63. GRB 250902B: AstroSat CZTI detection
  64. EP250903a: Global MASTER-Net observations report
  65. EP250903a: TRT optical observations
  66. EP250903a: Einstein Probe detection of an X-ray transient
  67. EP 250827B: Detection of supernova counterpart by LCO.
  68. EP250827b / AT 2025wkm: TRT optical observations
  69. EP250827b: NOT spectroscopic observations and AT 2025wkm classification as a broad-lined type-Ic supernova
  70. EP250827b: continued Liverpool Telescope observations
  71. GRB 250902B: SVOM/GRM observation
  72. EP250827b: SVOM/VT observation of AT 2025wkm
  73. LIGO/VIRGO/KAGRA S250818k: No evidence for radio variability of AT2025ulz in MeerKAT 3 GHz data
  74. GRB 250831A (SVOM trigger sb25083102): KAIT confirmation of stellar flare
  75. Fermi GRB 250902B: Global MASTER-Net observations report
  76. Fermi-LAT Gamma-ray Observations of IceCube-250831A
  77. GRB 250902A: Fermi GBM Detection
  78. GRB 250901A: Swift/UVOT Upper Limit
  79. IceCube-250831A: Upper limits from a search for additional neutrino events in IceCube
  80. LIGO/Virgo/KAGRA S250901cb: Updated Sky localization
  81. EP250827b: Liverpool Telescope observations
  82. GRB 250831A (SVOM trigger sb25083102): confirmation of a stellar flare by SVOM/VT
  83. GRB 250902A: SVOM/GRM observation
  84. EP250828a: Early near-infrared follow-up with MIRAGE on the MDM 1.3m telescope
  85. EP250901a: refined analysis of the EP-WXT and EP-FXT observations
  86. GRB 250901A: EP-FXT follow-up observation
  87. GRB 250901A: NOT optical observations
  88. GRB 250901A: SVOM/VT optical afterglow with VHF data
  89. LIGO/Virgo/KAGRA S250830bp: DECam GW-MMADS candidates
  90. GRB 250901A: LCO optical upper limit
  91. EP250827b: Swift observations of AT 2025wkm
  92. LIGO/Virgo/KAGRA S250830bp: DECam DESGW Epoch 1 Candidates
  93. EP250827b: Gemini Spectroscopy of AT 2025wkm
  94. LIGO/Virgo/KAGRA S250901cb: Identification of a GW compact binary merger candidate
  95. EP250831a: NOT optical observations and tentative afterglow candidate
  96. EP250827b: FTW Observations of AT 2025wkm
  97. EP250827b: Contemporaneous detection of EP X-ray flare EP250827b and ZTF transient ZTF25abmpngy/AT2025wkm
  98. GRB 250830C: Insight-HXMT detection
  99. EP250901a: Mephisto optical upper limits
  100. EP250901a: Global MASTER-Net observations report

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