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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"

28270 results found.

  1. GRB 250911A: MASTER optical counterpart observations
  2. EP250911a: SAO RAS optical observations
  3. GRB 250911A: Swift-XRT refined Analysis
  4. EP250911a: Swift-XRT observations
  5. EP250911a: Optical detection with Kinder observations
  6. GRB 250911A: Swift/UVOT Detection
  7. GRB 250910A / EP250910a: Swift-XRT afterglow detection
  8. GRB 250910A / EP250910a: SVOM/VT afterglow confirmation
  9. LIGO/Virgo/KAGRA S250911ac: Updated Sky localization and Source Classification
  10. GRB 250910A / EP250910a : VLT/HAWK-I NIR counterpart discovery
  11. EP250911a: COLIBRÍ optical observations
  12. LIGO/Virgo/KAGRA S250908y: Updated Sky localization
  13. EP250911a: LCO optical counterpart discovery
  14. EP250911a: Einstein Probe detection of an X-ray transient
  15. LIGO/Virgo/KAGRA S250911ac: Identification of a GW compact binary merger candidate
  16. GRB 250903A: SVOM/ECLAIRs refined analysis
  17. GRB 250911A: Enhanced Swift-XRT position
  18. GRB 250911A: Swift-XRT observations
  19. GRB 250911A: COLIBRÍ optical counterpart candidate
  20. LIGO/Virgo/KAGRA S250906ca: Updated Sky localization
  21. GRB 250910B: BALROG localization (Fermi Trigger 779223130 / GRB 250910786)
  22. GRB 250910A / EP250910a: VLT/HAWK-I near-infrared observations
  23. EP250910a/GRB 250910A: EP-WXT detection of a fast X-ray transient
  24. GRB 250910A: SVOM/VT optical upper limit
  25. GRB 250910A: LCO optical upper limit
  26. EP250908b/EP#01709240653: Swift/UVOT Detection
  27. EP#01709240653: Swift-XRT observations
  28. EP250908c: refined analysis of the EP-WXT and EP-FXT observations
  29. EP250908c: SVOM/VT optical observation
  30. EP250908c: VLT/FORS2 optical counterpart identification
  31. EP250908b: SVOM/VT optical candidate (Coordinate supplement for GCN 41758)
  32. EP250908b: SVOM/VT optical candidate
  33. Fermi GRB 250909A: Global MASTER-Net observations report
  34. EP250908c: Einstein Probe detection of an X-ray transient
  35. EP250908b: EP-WXT detection of a fast X-ray transient and EP-FXT observation
  36. LIGO/Virgo/KAGRA S250908y: Identification of a GW compact binary merger candidate
  37. GRB 250907A: GECAM-B detection
  38. GRB 250905A: Swift-BAT refined analysis
  39. Fermi-LAT Gamma-ray Observations of IceCube-250905A
  40. GRB 250903A: Swift-XRT afterglow detection
  41. LIGO/Virgo/KAGRA S250906ca: Identification of a GW compact binary merger candidate
  42. IceCube-250905A: Upper limits from a search for additional neutrino events in IceCube
  43. SVOM/sb25090605: detection of an X-ray transient from the LMXB 4U 0513-40
  44. EP250905a: Liverpool Telescope i-band upper limits
  45. LIGO/Virgo/KAGRA S250830bp: DECam/SOAR GW-MMADS updates
  46. LIGO/Virgo/KAGRA S250830bp: DECam DESGW Epoch 2 Candidates
  47. EP250905a: Liverpool Telescope observations
  48. EP250905a: refined analysis of the EP-WXT and EP-FXT observations
  49. EP250905b: EP-WXT detection of a fast X-ray transient
  50. GRB 250905A: Swift-XRT refined Analysis
  51. EP250905a: JinShan likely optical counterpart detection
  52. GRB 250904A: Swift-BAT refined analysis
  53. GRB 250905A: Swift/UVOT Upper Limits
  54. GRB 250901A - SVOM/ECLAIRs refined analysis
  55. EP250905a: Einstein Probe detection of an X-ray transient
  56. GRB250904A: Liverpool Telescope upper limits
  57. GRB 250905A: Enhanced Swift-XRT position
  58. GRB 250904A: Swift/UVOT Detection
  59. GRB 250903A: Swift/UVOT detection
  60. GRB 250904A: Swift-XRT refined Analysis
  61. LIGO/Virgo/KAGRA S250904cv: Updated Sky localization
  62. LIGO/Virgo/KAGRA S250904br: Updated Sky localization
  63. EP detected a brightening of LMXB 1ES 1735-26.9
  64. GRB 250905A: KAIT optical upper limit
  65. GRB 250905A: Swift detection of a burst
  66. GRB 250904A: Enhanced Swift-XRT position
  67. IceCube-Cascade 250903A: Upper limits from a search for additional neutrino events in IceCube
  68. GRB 250904A: TRT optical counterpart detection
  69. EP250827a and EP250827b: Upper limit from Fermi-GBM Observations
  70. GRB 250904A: Swift detection of a burst
  71. LIGO/Virgo/KAGRA S250904ae: Updated Sky localization
  72. GRB 250902A: VZLUSAT-2 detection
  73. LIGO/Virgo/KAGRA S250904cv: Identification of a GW compact binary merger candidate
  74. GRB 250903A: Swift-XRT observations
  75. EP250903a: Swift-XRT observations
  76. EP#01709201209: Swift-XRT observations
  77. EP250903a: retraction of the LCO candidate, and discovery of the likely counterpart
  78. EP-WXT trigger 01709201209: Liverpool Telescope upper limits
  79. GRB 250830C: VZLUSAT-2 detection
  80. EP250903a: refined analysis of the EP-WXT and EP-FXT observations
  81. LIGO/Virgo/KAGRA S250904br: Identification of a GW compact binary merger candidate
  82. LIGO/Virgo/KAGRA S250904ae: Identification of a GW compact binary merger candidate
  83. GRB 250903A: EP-FXT counterpart detection
  84. GRB 250902A: GECAM-B detection
  85. GRB 250903A: LCO optical observation
  86. GRB 250903A: LCO optical afterglow detection
  87. GRB 250903A: SVOM/VT optical confirmation with VHF data
  88. EP250901a: Mondy, Assy and SAO RAS optical limits
  89. EP250903a: LCO candidate counterpart discovery
  90. GRB 250903A: TRT optical counterpart detection
  91. EP250903a: TRT optical observations
  92. EP250903a: Einstein Probe detection of an X-ray transient
  93. EP 250827B: Detection of supernova counterpart by LCO.
  94. GRB 250902B: SVOM/GRM observation
  95. EP250827b: SVOM/VT observation of AT 2025wkm
  96. LIGO/VIRGO/KAGRA S250818k: No evidence for radio variability of AT2025ulz in MeerKAT 3 GHz data
  97. GRB 250831A (SVOM trigger sb25083102): KAIT confirmation of stellar flare
  98. Fermi-LAT Gamma-ray Observations of IceCube-250831A
  99. GRB 250902A: Fermi GBM Detection
  100. GRB 250901A: Swift/UVOT Upper Limit

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