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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"

41963 results found.

  1. GRB 250917B: Fermi GBM Observation
  2. GRB 250917B: Swift-XRT observations
  3. LIGO/Virgo/KAGRA S250917aq: Identification of a GW compact binary merger candidate
  4. Fermi GRB 250917B: Global MASTER-Net observations report
  5. GRB 250917B: Swift detection of a short burst
  6. GRB 250916A: GOTO optical counterpart candidate
  7. GRB 250917B: Fermi GBM Final Real-time Localization
  8. GRB 250917A: Fermi GBM Final Real-time Localization
  9. The EP-WXT trigger 01709241037 is likely a flaring star
  10. GRB 250916A: AstroSat CZTI detection of a bright long burst
  11. GRB 250910A: SVOM/ECLAIRs refined analysis
  12. EP250916a: Einstein Probe detection of an X-ray transient
  13. Fermi GRB 250916A: Global MASTER-Net observations report
  14. GRB 250916A: Fermi GBM Final Real-time Localization
  15. EP250827b: VLA Observations
  16. LIGO/Virgo/KAGRA S250818k: HCT optical follow-up
  17. SVOM/sb25091517: Confirmation of a stellar flare by SVOM/VT
  18. SVOM/sb25091517: FRAM-ORM stellar flare - transient observation
  19. SVOM/sb25091517: SVOM detection of an X-ray transient
  20. GRB 250912A: Swift/BAT-GUANO localization skymap of a possibly short burst
  21. GRB 250912A: SVOM/COLIBRÍ (FM-GFT) optical observations
  22. GRB 250912A: Swift-XRT observations
  23. GRB250912A: VLT/HAWK-I follow-up observations
  24. GRB 250912A: VLT observations
  25. GRB 250912A: Fermi GBM Observation
  26. GRB 250911A: Insight-HXMT detection
  27. GRB 250912A: SVOM/GRM analysis suggests a possible short GRB with extended emission
  28. GRB 250912A:SVOM/VT optical upper limit
  29. GRB 250912A: LCO optical upper limit
  30. The EP-WXT trigger 01709240768 is likely a flaring star
  31. Fermi GRB 250912A: Global MASTER-Net observations report
  32. EP250911a: Global MASTER-Net observations report
  33. GRB 250912A: SVOM detection of a burst
  34. GRB 250912A: Fermi GBM Final Real-time Localization
  35. IceCube-Cascade 250911A: Upper limits from a search for additional neutrino events in IceCube
  36. LIGO/Virgo/KAGRA S250912s: 2 counterpart neutrino candidate events from an IceCube neutrino search
  37. EP250908c: tentative VLT/FORS2 redshift z = 2.87
  38. EP250911a: Upper limit from Fermi-GBM Observations
  39. GRB 250911A: GECAM-B detection
  40. GRB 250911A: Swift-BAT refined analysis
  41. EP250911a: GTC/OSIRIS+ spectroscopic redshift z = 3.84
  42. LIGO/Virgo/KAGRA S250912f: Identification of a GW compact binary merger candidate
  43. EP250911a: refined analysis of the EP-WXT and EP-FXT observations
  44. GRB 250910B: SVOM/GRM observation
  45. EP250911a: SVOM/VT optical observation
  46. GRB 250911A: MASTER optical counterpart observations
  47. EP250911a: SAO RAS optical observations
  48. GRB 250911A: Swift-XRT refined Analysis
  49. GRB 250910C: Fermi GBM Final Localization Correction
  50. EP250911a: Swift-XRT observations
  51. EP250911a: Optical detection with Kinder observations
  52. GRB 250911A: Swift/UVOT Detection
  53. GRB 250910A / EP250910a: Swift-XRT afterglow detection
  54. GRB 250910A / EP250910a: SVOM/VT afterglow confirmation
  55. GRB 250909B: Insight-HXMT detection
  56. GRB 250909B: SVOM/GRM observation
  57. GRB 250910A / EP250910a : VLT/HAWK-I NIR counterpart discovery
  58. EP250911a: COLIBRÍ optical observations
  59. Fermi GRB 250910B: Global MASTER-Net observations report
  60. EP250911a: LCO optical counterpart discovery
  61. EP250910a: Global MASTER-Net observations report
  62. EP250911a: Einstein Probe detection of an X-ray transient
  63. GRB 250404A / EP250404a: spectroscopic redshift at z = 1.88 (correction to GCN 40084)
  64. LIGO/Virgo/KAGRA S250911ac: Identification of a GW compact binary merger candidate
  65. GRB 250903A: SVOM/ECLAIRs refined analysis
  66. GRB 250911A: Enhanced Swift-XRT position
  67. GRB 250911A: Swift-XRT observations
  68. GRB 250911A: COLIBRÍ optical counterpart candidate
  69. GRB 250911A: Swift detection of a burst
  70. GRB 250910B: BALROG localization (Fermi Trigger 779223130 / GRB 250910786)
  71. GRB 250910B: Fermi GBM Final Real-time Localization
  72. GRB 250910A / EP250910a: VLT/HAWK-I near-infrared observations
  73. EP250910a/GRB 250910A: EP-WXT detection of a fast X-ray transient
  74. GRB 250909B: AstroSat CZTI detection of a long burst
  75. GRB 250910A: SVOM/VT optical upper limit
  76. EP250908C: GROND observation of the fading optical counterpart
  77. GRB 250910A: LCO optical upper limit
  78. GRB 250909A: AstroSat CZTI detection
  79. GRB 250910A: SVOM/MXT possible afterglow detection
  80. GRB 250910A: SVOM detection of a faint burst
  81. LIGO/Virgo/KAGRA S250910b: Retraction of GW compact binary merger candidate
  82. GRB 250702B: Late time Chandra observations
  83. EP250908b/EP#01709240653: Swift/UVOT Detection
  84. EP#01709240653: Swift-XRT observations
  85. The EP-WXT trigger 01709240674 is triggered by the known source SS Cyg
  86. EP250908c: refined analysis of the EP-WXT and EP-FXT observations
  87. GRB 250907A: CALET Gamma-Ray Burst Monitor detection
  88. EP250908c: SVOM/VT optical observation
  89. EP250908c: VLT/FORS2 optical counterpart identification
  90. EP250908b: SVOM/VT optical candidate (Coordinate supplement for GCN 41758)
  91. EP250908b: SVOM/VT optical candidate
  92. EP250908c: Global MASTER-Net observations report
  93. Fermi GRB 250909A: Global MASTER-Net observations report
  94. EP250908c: Einstein Probe detection of an X-ray transient
  95. GRB 250909A: Fermi GBM Final Real-time Localization
  96. EP250908b: EP-WXT detection of a fast X-ray transient and EP-FXT observation
  97. EP#01709240652 (possibly EP250908a): FTW optical and NIR observations
  98. LIGO/Virgo/KAGRA S250908y: Identification of a GW compact binary merger candidate
  99. GRB 250907A: GECAM-B detection
  100. GRB 250905A: Swift-BAT refined analysis

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