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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.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

28292 results found.

  1. GRB 250912A: Swift/BAT-GUANO localization skymap of a possibly short burst
  2. GRB 250912A: SVOM/COLIBRÍ (FM-GFT) optical observations
  3. GRB 250912A: Swift-XRT observations
  4. GRB250912A: VLT/HAWK-I follow-up observations
  5. GRB 250912A: Fermi GBM Observation
  6. GRB 250912A: SVOM/GRM analysis suggests a possible short GRB with extended emission
  7. GRB 250912A:SVOM/VT optical upper limit
  8. GRB 250912A: LCO optical upper limit
  9. EP250911a: Global MASTER-Net observations report
  10. GRB 250912A: SVOM detection of a burst
  11. IceCube-Cascade 250911A: Upper limits from a search for additional neutrino events in IceCube
  12. LIGO/Virgo/KAGRA S250912s: 2 counterpart neutrino candidate events from an IceCube neutrino search
  13. EP250911a: Upper limit from Fermi-GBM Observations
  14. LIGO/Virgo/KAGRA S250912f: Updated Sky localization
  15. GRB 250911A: GECAM-B detection
  16. GRB 250911A: Swift-BAT refined analysis
  17. LIGO/Virgo/KAGRA S250912f: Identification of a GW compact binary merger candidate
  18. EP250911a: refined analysis of the EP-WXT and EP-FXT observations
  19. GRB 250910B: SVOM/GRM observation
  20. EP250911a: SVOM/VT optical observation
  21. GRB 250911A: MASTER optical counterpart observations
  22. EP250911a: SAO RAS optical observations
  23. GRB 250911A: Swift-XRT refined Analysis
  24. EP250911a: Swift-XRT observations
  25. EP250911a: Optical detection with Kinder observations
  26. GRB 250911A: Swift/UVOT Detection
  27. GRB 250910A / EP250910a: Swift-XRT afterglow detection
  28. GRB 250910A / EP250910a: SVOM/VT afterglow confirmation
  29. LIGO/Virgo/KAGRA S250911ac: Updated Sky localization and Source Classification
  30. GRB 250910A / EP250910a : VLT/HAWK-I NIR counterpart discovery
  31. EP250911a: COLIBRÍ optical observations
  32. LIGO/Virgo/KAGRA S250908y: Updated Sky localization
  33. EP250911a: LCO optical counterpart discovery
  34. EP250911a: Einstein Probe detection of an X-ray transient
  35. LIGO/Virgo/KAGRA S250911ac: Identification of a GW compact binary merger candidate
  36. GRB 250903A: SVOM/ECLAIRs refined analysis
  37. GRB 250911A: Enhanced Swift-XRT position
  38. GRB 250911A: Swift-XRT observations
  39. GRB 250911A: COLIBRÍ optical counterpart candidate
  40. LIGO/Virgo/KAGRA S250906ca: Updated Sky localization
  41. GRB 250910B: BALROG localization (Fermi Trigger 779223130 / GRB 250910786)
  42. GRB 250910A / EP250910a: VLT/HAWK-I near-infrared observations
  43. EP250910a/GRB 250910A: EP-WXT detection of a fast X-ray transient
  44. GRB 250910A: SVOM/VT optical upper limit
  45. GRB 250910A: LCO optical upper limit
  46. EP250908b/EP#01709240653: Swift/UVOT Detection
  47. EP#01709240653: Swift-XRT observations
  48. EP250908c: refined analysis of the EP-WXT and EP-FXT observations
  49. EP250908c: SVOM/VT optical observation
  50. EP250908c: VLT/FORS2 optical counterpart identification
  51. EP250908b: SVOM/VT optical candidate (Coordinate supplement for GCN 41758)
  52. EP250908b: SVOM/VT optical candidate
  53. Fermi GRB 250909A: Global MASTER-Net observations report
  54. EP250908c: Einstein Probe detection of an X-ray transient
  55. EP250908b: EP-WXT detection of a fast X-ray transient and EP-FXT observation
  56. LIGO/Virgo/KAGRA S250908y: Identification of a GW compact binary merger candidate
  57. GRB 250907A: GECAM-B detection
  58. GRB 250905A: Swift-BAT refined analysis
  59. Fermi-LAT Gamma-ray Observations of IceCube-250905A
  60. GRB 250903A: Swift-XRT afterglow detection
  61. LIGO/Virgo/KAGRA S250906ca: Identification of a GW compact binary merger candidate
  62. IceCube-250905A: Upper limits from a search for additional neutrino events in IceCube
  63. SVOM/sb25090605: detection of an X-ray transient from the LMXB 4U 0513-40
  64. EP250905a: Liverpool Telescope i-band upper limits
  65. LIGO/Virgo/KAGRA S250830bp: DECam/SOAR GW-MMADS updates
  66. LIGO/Virgo/KAGRA S250830bp: DECam DESGW Epoch 2 Candidates
  67. EP250905a: Liverpool Telescope observations
  68. EP250905a: refined analysis of the EP-WXT and EP-FXT observations
  69. EP250905b: EP-WXT detection of a fast X-ray transient
  70. GRB 250905A: Swift-XRT refined Analysis
  71. EP250905a: JinShan likely optical counterpart detection
  72. GRB 250904A: Swift-BAT refined analysis
  73. GRB 250905A: Swift/UVOT Upper Limits
  74. GRB 250901A - SVOM/ECLAIRs refined analysis
  75. EP250905a: Einstein Probe detection of an X-ray transient
  76. GRB250904A: Liverpool Telescope upper limits
  77. GRB 250905A: Enhanced Swift-XRT position
  78. GRB 250904A: Swift/UVOT Detection
  79. GRB 250903A: Swift/UVOT detection
  80. GRB 250904A: Swift-XRT refined Analysis
  81. LIGO/Virgo/KAGRA S250904cv: Updated Sky localization
  82. LIGO/Virgo/KAGRA S250904br: Updated Sky localization
  83. EP detected a brightening of LMXB 1ES 1735-26.9
  84. GRB 250905A: KAIT optical upper limit
  85. GRB 250905A: Swift detection of a burst
  86. GRB 250904A: Enhanced Swift-XRT position
  87. IceCube-Cascade 250903A: Upper limits from a search for additional neutrino events in IceCube
  88. GRB 250904A: TRT optical counterpart detection
  89. EP250827a and EP250827b: Upper limit from Fermi-GBM Observations
  90. GRB 250904A: Swift detection of a burst
  91. LIGO/Virgo/KAGRA S250904ae: Updated Sky localization
  92. GRB 250902A: VZLUSAT-2 detection
  93. LIGO/Virgo/KAGRA S250904cv: Identification of a GW compact binary merger candidate
  94. GRB 250903A: Swift-XRT observations
  95. EP250903a: Swift-XRT observations
  96. EP#01709201209: Swift-XRT observations
  97. EP250903a: retraction of the LCO candidate, and discovery of the likely counterpart
  98. EP-WXT trigger 01709201209: Liverpool Telescope upper limits
  99. GRB 250830C: VZLUSAT-2 detection
  100. EP250903a: refined analysis of the EP-WXT and EP-FXT observations

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