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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"

28231 results found.

  1. GRB 250920C: Swift detection of a burst
  2. LIGO/Virgo/KAGRA S250920bq: Coverage and upper limits from MAXI/GSC observations
  3. GRB 250920B: Swift detection of a burst with a bright optical counterpart.
  4. GRB 250920A: BALROG localization (Fermi Trigger 780029651 / GRB 250920121)
  5. GRB 250919A/EP250919a: SVOM/VT optical observation
  6. GRB 250916A: Mondy R-band optical observations
  7. GRB 250919A: Glowbug gamma-ray detection
  8. GRB 250919A: Fermi GBM Observation
  9. Fermi GRB 250918A: Global MASTER-Net observations report
  10. GRB 250919A / EP250919a: NuSTAR detection of bright prompt emission
  11. GRB 250918A: SVOM/GRM observation
  12. GRB 250919A: Swift-XRT afterglow detection
  13. GRB 250919A: SVOM/GRM observation of a very bright GRB
  14. GRB 250919A: BALROG localization (Fermi Trigger 779934537 / GRB 250919020)
  15. EP250919a: Einstein Probe detection of an X-ray transient
  16. GRB 250916A: Fermi GBM Observation
  17. GRB 250916A: KAIT optical observations
  18. GRB 250917B: VLT/HAWK-I near-infrared observations
  19. GRB 250916A: NuSTAR detection of the prompt emission
  20. GRB 250916A: further SAO RAS optical observations
  21. GRB 250917B: Swift-BAT refined analysis
  22. LIGO/Virgo/KAGRA S250918aw: 1 counterpart neutrino candidate event from an IceCube neutrino search
  23. GRB 250918A: BALROG localization (Fermi Trigger 779891543 / GRB 250918522)
  24. GRB 250917B: Swift/UVOT Upper Limits
  25. GRB 250916A: OSIRIS+/GTC redshift z = 2.015
  26. GRB 250916A: Swift-XRT observations
  27. GRB 250916A: MAO/AZT-22 optical observations
  28. GRB 250916A: SAO RAS optical observations
  29. GRB 250916A : GIT optical observations
  30. LIGO/Virgo/KAGRA S250917aq: Three counterpart neutrino candidates from IceCube neutrino searches
  31. LIGO/Virgo/KAGRA S250917aq: Updated Sky localization
  32. GRB 250916A: Glowbug gamma-ray detection
  33. GRB250917B: WFST optical observations
  34. GRB 250917B: Fermi GBM Observation
  35. GRB 250917B: Swift-XRT observations
  36. LIGO/Virgo/KAGRA S250917aq: Identification of a GW compact binary merger candidate
  37. GRB 250917B: Swift detection of a short burst
  38. GRB 250916A: AstroSat CZTI detection of a bright long burst
  39. EP250916a: Einstein Probe detection of an X-ray transient
  40. SVOM/sb25091517: SVOM detection of an X-ray transient
  41. GRB 250912A: Swift/BAT-GUANO localization skymap of a possibly short burst
  42. GRB 250912A: SVOM/COLIBRÍ (FM-GFT) optical observations
  43. GRB 250912A: Swift-XRT observations
  44. GRB250912A: VLT/HAWK-I follow-up observations
  45. GRB 250912A: Fermi GBM Observation
  46. GRB 250912A: SVOM/GRM analysis suggests a possible short GRB with extended emission
  47. GRB 250912A:SVOM/VT optical upper limit
  48. GRB 250912A: LCO optical upper limit
  49. EP250911a: Global MASTER-Net observations report
  50. GRB 250912A: SVOM detection of a burst
  51. IceCube-Cascade 250911A: Upper limits from a search for additional neutrino events in IceCube
  52. LIGO/Virgo/KAGRA S250912s: 2 counterpart neutrino candidate events from an IceCube neutrino search
  53. EP250911a: Upper limit from Fermi-GBM Observations
  54. LIGO/Virgo/KAGRA S250912f: Updated Sky localization
  55. GRB 250911A: GECAM-B detection
  56. GRB 250911A: Swift-BAT refined analysis
  57. LIGO/Virgo/KAGRA S250912f: Identification of a GW compact binary merger candidate
  58. EP250911a: refined analysis of the EP-WXT and EP-FXT observations
  59. GRB 250910B: SVOM/GRM observation
  60. EP250911a: SVOM/VT optical observation
  61. GRB 250911A: MASTER optical counterpart observations
  62. EP250911a: SAO RAS optical observations
  63. GRB 250911A: Swift-XRT refined Analysis
  64. EP250911a: Swift-XRT observations
  65. EP250911a: Optical detection with Kinder observations
  66. GRB 250911A: Swift/UVOT Detection
  67. GRB 250910A / EP250910a: Swift-XRT afterglow detection
  68. GRB 250910A / EP250910a: SVOM/VT afterglow confirmation
  69. LIGO/Virgo/KAGRA S250911ac: Updated Sky localization and Source Classification
  70. GRB 250910A / EP250910a : VLT/HAWK-I NIR counterpart discovery
  71. EP250911a: COLIBRÍ optical observations
  72. LIGO/Virgo/KAGRA S250908y: Updated Sky localization
  73. EP250911a: LCO optical counterpart discovery
  74. EP250911a: Einstein Probe detection of an X-ray transient
  75. LIGO/Virgo/KAGRA S250911ac: Identification of a GW compact binary merger candidate
  76. GRB 250903A: SVOM/ECLAIRs refined analysis
  77. GRB 250911A: Enhanced Swift-XRT position
  78. GRB 250911A: Swift-XRT observations
  79. GRB 250911A: COLIBRÍ optical counterpart candidate
  80. LIGO/Virgo/KAGRA S250906ca: Updated Sky localization
  81. GRB 250910B: BALROG localization (Fermi Trigger 779223130 / GRB 250910786)
  82. GRB 250910A / EP250910a: VLT/HAWK-I near-infrared observations
  83. EP250910a/GRB 250910A: EP-WXT detection of a fast X-ray transient
  84. GRB 250910A: SVOM/VT optical upper limit
  85. GRB 250910A: LCO optical upper limit
  86. EP250908b/EP#01709240653: Swift/UVOT Detection
  87. EP#01709240653: Swift-XRT observations
  88. EP250908c: refined analysis of the EP-WXT and EP-FXT observations
  89. EP250908c: SVOM/VT optical observation
  90. EP250908c: VLT/FORS2 optical counterpart identification
  91. EP250908b: SVOM/VT optical candidate (Coordinate supplement for GCN 41758)
  92. EP250908b: SVOM/VT optical candidate
  93. Fermi GRB 250909A: Global MASTER-Net observations report
  94. EP250908c: Einstein Probe detection of an X-ray transient
  95. EP250908b: EP-WXT detection of a fast X-ray transient and EP-FXT observation
  96. LIGO/Virgo/KAGRA S250908y: Identification of a GW compact binary merger candidate
  97. GRB 250907A: GECAM-B detection
  98. GRB 250905A: Swift-BAT refined analysis
  99. Fermi-LAT Gamma-ray Observations of IceCube-250905A
  100. GRB 250903A: Swift-XRT afterglow detection

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