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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"

28120 results found.

  1. GRB 250919A: BALROG localization (Fermi Trigger 779934537 / GRB 250919020)
  2. EP250919a: Einstein Probe detection of an X-ray transient
  3. GRB 250916A: Fermi GBM Observation
  4. GRB 250916A: KAIT optical observations
  5. GRB 250917B: VLT/HAWK-I near-infrared observations
  6. GRB 250916A: NuSTAR detection of the prompt emission
  7. GRB 250916A: further SAO RAS optical observations
  8. GRB 250917B: Swift-BAT refined analysis
  9. LIGO/Virgo/KAGRA S250918aw: 1 counterpart neutrino candidate event from an IceCube neutrino search
  10. GRB 250918A: BALROG localization (Fermi Trigger 779891543 / GRB 250918522)
  11. GRB 250917B: Swift/UVOT Upper Limits
  12. GRB 250916A: OSIRIS+/GTC redshift z = 2.015
  13. GRB 250916A: Swift-XRT observations
  14. GRB 250916A: MAO/AZT-22 optical observations
  15. GRB 250916A: SAO RAS optical observations
  16. GRB 250916A : GIT optical observations
  17. LIGO/Virgo/KAGRA S250917aq: Three counterpart neutrino candidates from IceCube neutrino searches
  18. LIGO/Virgo/KAGRA S250917aq: Updated Sky localization
  19. GRB 250916A: Glowbug gamma-ray detection
  20. GRB250917B: WFST optical observations
  21. GRB 250917B: Fermi GBM Observation
  22. GRB 250917B: Swift-XRT observations
  23. LIGO/Virgo/KAGRA S250917aq: Identification of a GW compact binary merger candidate
  24. GRB 250917B: Swift detection of a short burst
  25. GRB 250916A: AstroSat CZTI detection of a bright long burst
  26. EP250916a: Einstein Probe detection of an X-ray transient
  27. SVOM/sb25091517: SVOM detection of an X-ray transient
  28. GRB 250912A: Swift/BAT-GUANO localization skymap of a possibly short burst
  29. GRB 250912A: SVOM/COLIBRÍ (FM-GFT) optical observations
  30. GRB 250912A: Swift-XRT observations
  31. GRB250912A: VLT/HAWK-I follow-up observations
  32. GRB 250912A: Fermi GBM Observation
  33. GRB 250912A: SVOM/GRM analysis suggests a possible short GRB with extended emission
  34. GRB 250912A:SVOM/VT optical upper limit
  35. GRB 250912A: LCO optical upper limit
  36. EP250911a: Global MASTER-Net observations report
  37. GRB 250912A: SVOM detection of a burst
  38. IceCube-Cascade 250911A: Upper limits from a search for additional neutrino events in IceCube
  39. LIGO/Virgo/KAGRA S250912s: 2 counterpart neutrino candidate events from an IceCube neutrino search
  40. EP250911a: Upper limit from Fermi-GBM Observations
  41. LIGO/Virgo/KAGRA S250912f: Updated Sky localization
  42. GRB 250911A: GECAM-B detection
  43. GRB 250911A: Swift-BAT refined analysis
  44. LIGO/Virgo/KAGRA S250912f: Identification of a GW compact binary merger candidate
  45. EP250911a: refined analysis of the EP-WXT and EP-FXT observations
  46. GRB 250910B: SVOM/GRM observation
  47. EP250911a: SVOM/VT optical observation
  48. GRB 250911A: MASTER optical counterpart observations
  49. EP250911a: SAO RAS optical observations
  50. GRB 250911A: Swift-XRT refined Analysis
  51. EP250911a: Swift-XRT observations
  52. EP250911a: Optical detection with Kinder observations
  53. GRB 250911A: Swift/UVOT Detection
  54. GRB 250910A / EP250910a: Swift-XRT afterglow detection
  55. GRB 250910A / EP250910a: SVOM/VT afterglow confirmation
  56. LIGO/Virgo/KAGRA S250911ac: Updated Sky localization and Source Classification
  57. GRB 250910A / EP250910a : VLT/HAWK-I NIR counterpart discovery
  58. EP250911a: COLIBRÍ optical observations
  59. LIGO/Virgo/KAGRA S250908y: Updated Sky localization
  60. EP250911a: LCO optical counterpart discovery
  61. EP250911a: Einstein Probe detection of an X-ray transient
  62. LIGO/Virgo/KAGRA S250911ac: Identification of a GW compact binary merger candidate
  63. GRB 250903A: SVOM/ECLAIRs refined analysis
  64. GRB 250911A: Enhanced Swift-XRT position
  65. GRB 250911A: Swift-XRT observations
  66. GRB 250911A: COLIBRÍ optical counterpart candidate
  67. LIGO/Virgo/KAGRA S250906ca: Updated Sky localization
  68. GRB 250910B: BALROG localization (Fermi Trigger 779223130 / GRB 250910786)
  69. GRB 250910A / EP250910a: VLT/HAWK-I near-infrared observations
  70. EP250910a/GRB 250910A: EP-WXT detection of a fast X-ray transient
  71. GRB 250910A: SVOM/VT optical upper limit
  72. GRB 250910A: LCO optical upper limit
  73. EP250908b/EP#01709240653: Swift/UVOT Detection
  74. EP#01709240653: Swift-XRT observations
  75. EP250908c: refined analysis of the EP-WXT and EP-FXT observations
  76. EP250908c: SVOM/VT optical observation
  77. EP250908c: VLT/FORS2 optical counterpart identification
  78. EP250908b: SVOM/VT optical candidate (Coordinate supplement for GCN 41758)
  79. EP250908b: SVOM/VT optical candidate
  80. Fermi GRB 250909A: Global MASTER-Net observations report
  81. EP250908c: Einstein Probe detection of an X-ray transient
  82. EP250908b: EP-WXT detection of a fast X-ray transient and EP-FXT observation
  83. LIGO/Virgo/KAGRA S250908y: Identification of a GW compact binary merger candidate
  84. GRB 250907A: GECAM-B detection
  85. GRB 250905A: Swift-BAT refined analysis
  86. Fermi-LAT Gamma-ray Observations of IceCube-250905A
  87. GRB 250903A: Swift-XRT afterglow detection
  88. LIGO/Virgo/KAGRA S250906ca: Identification of a GW compact binary merger candidate
  89. IceCube-250905A: Upper limits from a search for additional neutrino events in IceCube
  90. SVOM/sb25090605: detection of an X-ray transient from the LMXB 4U 0513-40
  91. EP250905a: Liverpool Telescope i-band upper limits
  92. LIGO/Virgo/KAGRA S250830bp: DECam/SOAR GW-MMADS updates
  93. LIGO/Virgo/KAGRA S250830bp: DECam DESGW Epoch 2 Candidates
  94. EP250905a: Liverpool Telescope observations
  95. EP250905a: refined analysis of the EP-WXT and EP-FXT observations
  96. EP250905b: EP-WXT detection of a fast X-ray transient
  97. GRB 250905A: Swift-XRT refined Analysis
  98. EP250905a: JinShan likely optical counterpart detection
  99. GRB 250904A: Swift-BAT refined analysis
  100. GRB 250905A: Swift/UVOT Upper Limits

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