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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"
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submitter:"Judith Racusin"

28123 results found.

  1. EP250905a: refined analysis of the EP-WXT and EP-FXT observations
  2. EP250905b: EP-WXT detection of a fast X-ray transient
  3. GRB 250905A: Swift-XRT refined Analysis
  4. EP250905a: JinShan likely optical counterpart detection
  5. GRB 250904A: Swift-BAT refined analysis
  6. GRB 250905A: Swift/UVOT Upper Limits
  7. GRB 250901A - SVOM/ECLAIRs refined analysis
  8. EP250905a: Einstein Probe detection of an X-ray transient
  9. GRB250904A: Liverpool Telescope upper limits
  10. GRB 250905A: Enhanced Swift-XRT position
  11. GRB 250904A: Swift/UVOT Detection
  12. GRB 250903A: Swift/UVOT detection
  13. GRB 250904A: Swift-XRT refined Analysis
  14. LIGO/Virgo/KAGRA S250904cv: Updated Sky localization
  15. LIGO/Virgo/KAGRA S250904br: Updated Sky localization
  16. EP detected a brightening of LMXB 1ES 1735-26.9
  17. GRB 250905A: KAIT optical upper limit
  18. GRB 250905A: Swift detection of a burst
  19. GRB 250904A: Enhanced Swift-XRT position
  20. IceCube-Cascade 250903A: Upper limits from a search for additional neutrino events in IceCube
  21. GRB 250904A: TRT optical counterpart detection
  22. EP250827a and EP250827b: Upper limit from Fermi-GBM Observations
  23. GRB 250904A: Swift detection of a burst
  24. LIGO/Virgo/KAGRA S250904ae: Updated Sky localization
  25. GRB 250902A: VZLUSAT-2 detection
  26. LIGO/Virgo/KAGRA S250904cv: Identification of a GW compact binary merger candidate
  27. GRB 250903A: Swift-XRT observations
  28. EP250903a: Swift-XRT observations
  29. EP#01709201209: Swift-XRT observations
  30. EP250903a: retraction of the LCO candidate, and discovery of the likely counterpart
  31. EP-WXT trigger 01709201209: Liverpool Telescope upper limits
  32. GRB 250830C: VZLUSAT-2 detection
  33. EP250903a: refined analysis of the EP-WXT and EP-FXT observations
  34. LIGO/Virgo/KAGRA S250904br: Identification of a GW compact binary merger candidate
  35. LIGO/Virgo/KAGRA S250904ae: Identification of a GW compact binary merger candidate
  36. GRB 250903A: EP-FXT counterpart detection
  37. GRB 250902A: GECAM-B detection
  38. GRB 250903A: LCO optical observation
  39. GRB 250903A: LCO optical afterglow detection
  40. GRB 250903A: SVOM/VT optical confirmation with VHF data
  41. EP250901a: Mondy, Assy and SAO RAS optical limits
  42. EP250903a: LCO candidate counterpart discovery
  43. GRB 250903A: TRT optical counterpart detection
  44. EP250903a: TRT optical observations
  45. EP250903a: Einstein Probe detection of an X-ray transient
  46. EP 250827B: Detection of supernova counterpart by LCO.
  47. GRB 250902B: SVOM/GRM observation
  48. EP250827b: SVOM/VT observation of AT 2025wkm
  49. LIGO/VIRGO/KAGRA S250818k: No evidence for radio variability of AT2025ulz in MeerKAT 3 GHz data
  50. GRB 250831A (SVOM trigger sb25083102): KAIT confirmation of stellar flare
  51. Fermi-LAT Gamma-ray Observations of IceCube-250831A
  52. GRB 250902A: Fermi GBM Detection
  53. GRB 250901A: Swift/UVOT Upper Limit
  54. IceCube-250831A: Upper limits from a search for additional neutrino events in IceCube
  55. GRB 250830B: Swift-XRT afterglow detection
  56. LIGO/Virgo/KAGRA S250902av: 1 counterpart neutrino candidate event from an IceCube neutrino search
  57. LIGO/Virgo/KAGRA S250901cb: Updated Sky localization
  58. GRB 250831A (SVOM trigger sb25083102): confirmation of a stellar flare by SVOM/VT
  59. GRB 250902A: SVOM/GRM observation
  60. EP250828a: Early near-infrared follow-up with MIRAGE on the MDM 1.3m telescope
  61. EP250901a: refined analysis of the EP-WXT and EP-FXT observations
  62. IceCube-Cascade 250828A: Upper limits from a search for additional neutrino events in IceCube
  63. GRB 250901A: SVOM/VT optical afterglow with VHF data
  64. GRB 250901A: Swift-XRT afterglow detection
  65. EP250901a: Swift-XRT observations
  66. LIGO/Virgo/KAGRA S250830bp: DECam GW-MMADS candidates
  67. GRB 250901A: LCO optical upper limit
  68. LIGO/Virgo/KAGRA S250830bp: DECam DESGW Epoch 1 Candidates
  69. EP250827b: Gemini Spectroscopy of AT 2025wkm
  70. LIGO/Virgo/KAGRA S250901cb: Identification of a GW compact binary merger candidate
  71. EP250831a: NOT optical observations and tentative afterglow candidate
  72. EP250827b: Contemporaneous detection of EP X-ray flare EP250827b and ZTF transient ZTF25abmpngy/AT2025wkm
  73. GRB 250901A: SVOM detection of a burst
  74. EP250901a: Mephisto optical upper limits
  75. GRB 250830C: GECAM-B detection
  76. EP250901a: Einstein Probe detection of an X-ray transient
  77. LIGO/Virgo/KAGRA S250830m: Updated Sky localization
  78. EP250831a: Swift-XRT observations
  79. LIGO/Virgo/KAGRA S250831cc: Coverage and upper limits from MAXI/GSC observations
  80. EP250831a: EP-WXT detection of a fast X-ray transient
  81. GRB 250831A: Swift-XRT counterpart detection
  82. GRB 250831A: SVOM/COLIBRÍ (FM-GFT) optical upper limit
  83. GRB 250831A: SVOM/VT upper limit with VHF data
  84. GRB 250831A: SVOM detection of a soft burst
  85. GRB 250830B: Swift-XRT observations
  86. EP250830a/GRB 250830B: Einstein Probe detection of an X-ray transient and Swift/XRT follow-up
  87. LIGO/Virgo/KAGRA S250830bp: Coverage and upper limits from MAXI/GSC observations
  88. LIGO/Virgo/KAGRA S250830bp GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  89. LIGO/Virgo/KAGRA S250830bp: NED Galaxies in the 4-Update Localization Volume
  90. LIGO/Virgo/KAGRA S250830bp: Updated Sky localization, EM Bright Classification, and Source Classification
  91. LIGO/Virgo/KAGRA S250830bp: Identification of a GW compact binary merger candidate
  92. EP-WXT trigger 01709200994: Liverpool Telescope upper limits
  93. EP-WXT trigger 01709200994: confirmation of a stellar flare by BOOTES-6
  94. GRB 250830B: MAXI/GSC detection
  95. LIGO/Virgo/KAGRA S250830m: Identification of a GW compact binary merger candidate
  96. GRB 250830A / MAXI J0853+337: MAXI/GSC detection
  97. GRB 250828B: Swift-BAT refined analysis
  98. LIGO/Virgo/KAGRA S250725j: Observations with the NSF-DOE Vera C. Rubin Observatory
  99. LIGO/Virgo/KAGRA S250818k: MeerKAT detection of an increase in radio flux from AT2025ulz
  100. EP250828a: refined analysis of the EP-WXT and EP-FXT observations

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