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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"

45692 results found.

  1. LIGO/Virgo/KAGRA S250912f: Updated Sky localization
  2. GRB 250911A: GECAM-B detection
  3. GRB 250911A: Swift-BAT refined analysis
  4. EP250911a: GTC/OSIRIS+ spectroscopic redshift z = 3.84
  5. LIGO/Virgo/KAGRA S250912f: Identification of a GW compact binary merger candidate
  6. EP250911a: refined analysis of the EP-WXT and EP-FXT observations
  7. GRB 250910B: SVOM/GRM observation
  8. EP250911a: SVOM/VT optical observation
  9. GRB 250911A: MASTER optical counterpart observations
  10. EP250911a: SAO RAS optical observations
  11. GRB 250911A: Swift-XRT refined Analysis
  12. GRB 250910C: Fermi GBM Final Localization Correction
  13. EP250911a: Swift-XRT observations
  14. EP250911a: Optical detection with Kinder observations
  15. GRB 250911A: Swift/UVOT Detection
  16. GRB 250910A / EP250910a: Swift-XRT afterglow detection
  17. GRB 250910A / EP250910a: SVOM/VT afterglow confirmation
  18. GRB 250909B: Insight-HXMT detection
  19. GRB 250909B: SVOM/GRM observation
  20. LIGO/Virgo/KAGRA S250911ac: Updated Sky localization and Source Classification
  21. GRB 250910A / EP250910a : VLT/HAWK-I NIR counterpart discovery
  22. EP250911a: COLIBRÍ optical observations
  23. LIGO/Virgo/KAGRA S250908y: Updated Sky localization
  24. Fermi GRB 250910B: Global MASTER-Net observations report
  25. EP250911a: LCO optical counterpart discovery
  26. EP250910a: Global MASTER-Net observations report
  27. EP250911a: Einstein Probe detection of an X-ray transient
  28. GRB 250404A / EP250404a: spectroscopic redshift at z = 1.88 (correction to GCN 40084)
  29. LIGO/Virgo/KAGRA S250911ac: Identification of a GW compact binary merger candidate
  30. GRB 250903A: SVOM/ECLAIRs refined analysis
  31. GRB 250911A: Enhanced Swift-XRT position
  32. GRB 250911A: Swift-XRT observations
  33. GRB 250911A: COLIBRÍ optical counterpart candidate
  34. GRB 250911A: Swift detection of a burst
  35. LIGO/Virgo/KAGRA S250906ca: Updated Sky localization
  36. GRB 250910B: BALROG localization (Fermi Trigger 779223130 / GRB 250910786)
  37. GRB 250910B: Fermi GBM Final Real-time Localization
  38. GRB 250910A / EP250910a: VLT/HAWK-I near-infrared observations
  39. EP250910a/GRB 250910A: EP-WXT detection of a fast X-ray transient
  40. GRB 250909B: AstroSat CZTI detection of a long burst
  41. GRB 250910A: SVOM/VT optical upper limit
  42. EP250908C: GROND observation of the fading optical counterpart
  43. GRB 250910A: LCO optical upper limit
  44. GRB 250909A: AstroSat CZTI detection
  45. GRB 250910A: SVOM/MXT possible afterglow detection
  46. GRB 250910A: SVOM detection of a faint burst
  47. LIGO/Virgo/KAGRA S250910b: Retraction of GW compact binary merger candidate
  48. GRB 250702B: Late time Chandra observations
  49. EP250908b/EP#01709240653: Swift/UVOT Detection
  50. EP#01709240653: Swift-XRT observations
  51. The EP-WXT trigger 01709240674 is triggered by the known source SS Cyg
  52. EP250908c: refined analysis of the EP-WXT and EP-FXT observations
  53. GRB 250907A: CALET Gamma-Ray Burst Monitor detection
  54. EP250908c: SVOM/VT optical observation
  55. EP250908c: VLT/FORS2 optical counterpart identification
  56. EP250908b: SVOM/VT optical candidate (Coordinate supplement for GCN 41758)
  57. EP250908b: SVOM/VT optical candidate
  58. The EP-WXT trigger EP250908a/01709240652 is not a real source
  59. EP250908c: Global MASTER-Net observations report
  60. Fermi GRB 250909A: Global MASTER-Net observations report
  61. EP250908c: Einstein Probe detection of an X-ray transient
  62. GRB 250909A: Fermi GBM Final Real-time Localization
  63. EP250908b: EP-WXT detection of a fast X-ray transient and EP-FXT observation
  64. EP#01709240652 (possibly EP250908a): FTW optical and NIR observations
  65. LIGO/Virgo/KAGRA S250908y: Identification of a GW compact binary merger candidate
  66. GRB 250907A: GECAM-B detection
  67. GRB 250905A: Swift-BAT refined analysis
  68. Fermi-LAT Gamma-ray Observations of IceCube-250905A
  69. GRB 250903A: Swift-XRT afterglow detection
  70. LIGO/Virgo/KAGRA S250906ca: Identification of a GW compact binary merger candidate
  71. IceCube-250905A: Upper limits from a search for additional neutrino events in IceCube
  72. SVOM/sb25090605: detection of an X-ray transient from the LMXB 4U 0513-40
  73. EP250905a: Liverpool Telescope i-band upper limits
  74. LIGO/Virgo/KAGRA S250830bp: DECam/SOAR GW-MMADS updates
  75. EP250905b: EP-FXT follow-up observation
  76. LIGO/Virgo/KAGRA S250830bp: DECam DESGW Epoch 2 Candidates
  77. EP250905a: Liverpool Telescope observations
  78. EP250905a: refined analysis of the EP-WXT and EP-FXT observations
  79. EP250905b: Global MASTER-Net observations report
  80. EP250905b: EP-WXT detection of a fast X-ray transient
  81. EP250905a: FTW one optical and multiple NIR counterpart candidates
  82. GRB 250905A: Swift-XRT refined Analysis
  83. EP250905a: JinShan likely optical counterpart detection
  84. IceCube-250905A - IceCube observation of a high-energy neutrino candidate track-like event
  85. GRB 250904A: Swift-BAT refined analysis
  86. IceCube Alert 250905.84: Global MASTER-Net observations report
  87. GRB 250905A: Swift/UVOT Upper Limits
  88. EP250905a: Global MASTER-Net observations report
  89. GRB 250901A - SVOM/ECLAIRs refined analysis
  90. EP250905a: Einstein Probe detection of an X-ray transient
  91. GRB 250905B: Fermi GBM Final Localization
  92. GRB250904A: Liverpool Telescope upper limits
  93. GRB 250905A: Enhanced Swift-XRT position
  94. GRB 250904A: Swift/UVOT Detection
  95. GRB 250903A: Swift/UVOT detection
  96. GRB 250904A: Swift-XRT refined Analysis
  97. LIGO/Virgo/KAGRA S250904cv: Updated Sky localization
  98. LIGO/Virgo/KAGRA S250904br: Updated Sky localization
  99. EP detected a brightening of LMXB 1ES 1735-26.9
  100. GRB 250905A: KAIT optical upper limit

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