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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"

28232 results found.

  1. GRB 250920B: SVOM/C-GFT optical observations
  2. GRB 250919A / EP250919a: LCO optical observation
  3. GRB 250920C: Swift detection of a burst
  4. LIGO/Virgo/KAGRA S250920bq: Coverage and upper limits from MAXI/GSC observations
  5. GRB 250920B: Swift detection of a burst with a bright optical counterpart.
  6. GRB 250920A: BALROG localization (Fermi Trigger 780029651 / GRB 250920121)
  7. GRB 250919A/EP250919a: SVOM/VT optical observation
  8. GRB 250916A: Mondy R-band optical observations
  9. GRB 250919A: Glowbug gamma-ray detection
  10. GRB 250919A: Fermi GBM Observation
  11. Fermi GRB 250918A: Global MASTER-Net observations report
  12. GRB 250919A / EP250919a: NuSTAR detection of bright prompt emission
  13. GRB 250918A: SVOM/GRM observation
  14. GRB 250919A: Swift-XRT afterglow detection
  15. GRB 250919A: SVOM/GRM observation of a very bright GRB
  16. GRB 250919A: BALROG localization (Fermi Trigger 779934537 / GRB 250919020)
  17. EP250919a: Einstein Probe detection of an X-ray transient
  18. GRB 250916A: Fermi GBM Observation
  19. GRB 250916A: KAIT optical observations
  20. GRB 250917B: VLT/HAWK-I near-infrared observations
  21. GRB 250916A: NuSTAR detection of the prompt emission
  22. GRB 250916A: further SAO RAS optical observations
  23. GRB 250917B: Swift-BAT refined analysis
  24. LIGO/Virgo/KAGRA S250918aw: 1 counterpart neutrino candidate event from an IceCube neutrino search
  25. GRB 250918A: BALROG localization (Fermi Trigger 779891543 / GRB 250918522)
  26. GRB 250917B: Swift/UVOT Upper Limits
  27. GRB 250916A: OSIRIS+/GTC redshift z = 2.015
  28. GRB 250916A: Swift-XRT observations
  29. GRB 250916A: MAO/AZT-22 optical observations
  30. GRB 250916A: SAO RAS optical observations
  31. GRB 250916A : GIT optical observations
  32. LIGO/Virgo/KAGRA S250917aq: Three counterpart neutrino candidates from IceCube neutrino searches
  33. LIGO/Virgo/KAGRA S250917aq: Updated Sky localization
  34. GRB 250916A: Glowbug gamma-ray detection
  35. GRB250917B: WFST optical observations
  36. GRB 250917B: Fermi GBM Observation
  37. GRB 250917B: Swift-XRT observations
  38. LIGO/Virgo/KAGRA S250917aq: Identification of a GW compact binary merger candidate
  39. GRB 250917B: Swift detection of a short burst
  40. GRB 250916A: AstroSat CZTI detection of a bright long burst
  41. EP250916a: Einstein Probe detection of an X-ray transient
  42. SVOM/sb25091517: SVOM detection of an X-ray transient
  43. GRB 250912A: Swift/BAT-GUANO localization skymap of a possibly short burst
  44. GRB 250912A: SVOM/COLIBRÍ (FM-GFT) optical observations
  45. GRB 250912A: Swift-XRT observations
  46. GRB250912A: VLT/HAWK-I follow-up observations
  47. GRB 250912A: Fermi GBM Observation
  48. GRB 250912A: SVOM/GRM analysis suggests a possible short GRB with extended emission
  49. GRB 250912A:SVOM/VT optical upper limit
  50. GRB 250912A: LCO optical upper limit
  51. EP250911a: Global MASTER-Net observations report
  52. GRB 250912A: SVOM detection of a burst
  53. IceCube-Cascade 250911A: Upper limits from a search for additional neutrino events in IceCube
  54. LIGO/Virgo/KAGRA S250912s: 2 counterpart neutrino candidate events from an IceCube neutrino search
  55. EP250911a: Upper limit from Fermi-GBM Observations
  56. LIGO/Virgo/KAGRA S250912f: Updated Sky localization
  57. GRB 250911A: GECAM-B detection
  58. GRB 250911A: Swift-BAT refined analysis
  59. LIGO/Virgo/KAGRA S250912f: Identification of a GW compact binary merger candidate
  60. EP250911a: refined analysis of the EP-WXT and EP-FXT observations
  61. GRB 250910B: SVOM/GRM observation
  62. EP250911a: SVOM/VT optical observation
  63. GRB 250911A: MASTER optical counterpart observations
  64. EP250911a: SAO RAS optical observations
  65. GRB 250911A: Swift-XRT refined Analysis
  66. EP250911a: Swift-XRT observations
  67. EP250911a: Optical detection with Kinder observations
  68. GRB 250911A: Swift/UVOT Detection
  69. GRB 250910A / EP250910a: Swift-XRT afterglow detection
  70. GRB 250910A / EP250910a: SVOM/VT afterglow confirmation
  71. LIGO/Virgo/KAGRA S250911ac: Updated Sky localization and Source Classification
  72. GRB 250910A / EP250910a : VLT/HAWK-I NIR counterpart discovery
  73. EP250911a: COLIBRÍ optical observations
  74. LIGO/Virgo/KAGRA S250908y: Updated Sky localization
  75. EP250911a: LCO optical counterpart discovery
  76. EP250911a: Einstein Probe detection of an X-ray transient
  77. LIGO/Virgo/KAGRA S250911ac: Identification of a GW compact binary merger candidate
  78. GRB 250903A: SVOM/ECLAIRs refined analysis
  79. GRB 250911A: Enhanced Swift-XRT position
  80. GRB 250911A: Swift-XRT observations
  81. GRB 250911A: COLIBRÍ optical counterpart candidate
  82. LIGO/Virgo/KAGRA S250906ca: Updated Sky localization
  83. GRB 250910B: BALROG localization (Fermi Trigger 779223130 / GRB 250910786)
  84. GRB 250910A / EP250910a: VLT/HAWK-I near-infrared observations
  85. EP250910a/GRB 250910A: EP-WXT detection of a fast X-ray transient
  86. GRB 250910A: SVOM/VT optical upper limit
  87. GRB 250910A: LCO optical upper limit
  88. EP250908b/EP#01709240653: Swift/UVOT Detection
  89. EP#01709240653: Swift-XRT observations
  90. EP250908c: refined analysis of the EP-WXT and EP-FXT observations
  91. EP250908c: SVOM/VT optical observation
  92. EP250908c: VLT/FORS2 optical counterpart identification
  93. EP250908b: SVOM/VT optical candidate (Coordinate supplement for GCN 41758)
  94. EP250908b: SVOM/VT optical candidate
  95. Fermi GRB 250909A: Global MASTER-Net observations report
  96. EP250908c: Einstein Probe detection of an X-ray transient
  97. EP250908b: EP-WXT detection of a fast X-ray transient and EP-FXT observation
  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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