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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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').

2804 results found.

  1. LIGO/Virgo/KAGRA S240422ed: A transient discovered from Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  2. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  3. XMM-Newton observation of EP240426a
  4. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  5. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  6. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  7. LXT240402A/GRB240402B: Chandra X-ray detection
  8. GRB 240415B: Swift-XRT observations
  9. GRB 240415A: Swift-XRT refined Analysis
  10. GRB 240421B: Swift-XRT refined Analysis
  11. EP240420a: detection of fading X-ray emission with refined position by EP-FXT
  12. GRB240418A - Candidate afterglow from NIRES
  13. GRB 240419B: Swift-XRT refined Analysis
  14. GRB 240419A: Swift-XRT refined Analysis
  15. GRB 240418A: Swift-XRT refined Analysis
  16. EP240414a: EP-FXT follow-up observation
  17. LXT 240402A/GRB 240402B: Swift follow-up observations
  18. GRB 240414A: Swift-XRT refined Analysis
  19. EP240413a: possible detection of the X-ray emission with EP-FXT after 14 hours
  20. GRB 240411B: Swift-XRT refined Analysis
  21. Fermi GRB 240407A: Global MASTER-Net observations report
  22. LXT 240402A: EP-FXT detection of the X-ray afterglow
  23. X-ray transient EP 240315a: Second epoch Chandra observations
  24. X-ray transient EP 240315a: Chandra observations
  25. GRB 240225B: Swift-XRT afterglow detection
  26. GRB 240215A: Swift-XRT afterglow detection
  27. GRB 240225B: Swift-XRT observations
  28. Transient EPW20240219aa: Kp-band imaging observations with NIRES
  29. GRB 240222A: Swift-XRT refined Analysis
  30. GRB 240218A: LBT H-band detection
  31. Konus-Wind detection of GRB 240218A
  32. GRB 240218A: Swift-XRT refined Analysis
  33. Fermi GRB 240216A: Global MASTER-Net observations report
  34. GRB 240128A: Further Swift-XRT observations
  35. GRB240204A: Swift/UVOT Upper Limits
  36. GRB 240128A: Swift-XRT observations
  37. GRB 240122A: Swift/UVOT Upper Limits
  38. GRB 240123A: Swift-XRT refined Analysis
  39. GRB 240122A: Swift-XRT afterglow detection
  40. GRB 240118A: Swift-XRT afterglow detection
  41. GRB 240112C: Swift-XRT refined Analysis
  42. GRB 231220A: Swift-UVOT upper limit
  43. GRB 240101B: Swift-XRT refined Analysis
  44. GRB 240102A: Swift-XRT refined Analysis
  45. GRB 240101B: Swift/UVOT Upper Limits
  46. GRB 240101A: Swift-XRT refined Analysis
  47. GRB 231230A: Swift-XRT refined Analysis
  48. Fermi trigger No 725592555: Global MASTER-Net observations report
  49. GRB 231222B: Swift-XRT afterglow detection
  50. GRB 231220A: Swift-XRT follow-up observations
  51. GRB 231216A: Swift-XRT refined Analysis
  52. GRB 231215A: Swift-XRT refined Analysis
  53. GRB 231214A: Swift-XRT refined Analysis
  54. GRB 231210B: Swift-XRT refined Analysis
  55. GRB 231205B: Swift-XRT refined Analysis
  56. GRB 231129C: Swift-XRT afterglow detection
  57. GRB 231129B: Swift-XRT observations
  58. GRB 231129C: Swift-XRT observations
  59. GRB 231129A: Swift-XRT refined Analysis
  60. GRB 231123C: Insight-HXMT/HE detection
  61. GRB 231115A: XMM-Newton observation
  62. GRB 231117A: GTC Near-Infrared Observations
  63. GRB 231117A: Swift-XRT refined Analysis
  64. GRB 231118A: Swift-XRT refined Analysis
  65. GRB 231115A: NuSTAR Follow-Up Observations
  66. GRB 231115A: Swift-XRT and Swift-UVOT observations
  67. GRB 231115A: archival Chandra X-ray observations
  68. GRB 231110A: Swift-UVOT Upper Limits
  69. GRB 231111A: Swift-XRT refined Analysis
  70. GRB 231110A: Swift-XRT afterglow detection
  71. GRB 231104A: Swift-XRT refined Analysis
  72. GRB 231017A: Swift-XRT observations
  73. GRB 230906A: optical counterpart
  74. GRB 230911A: Swift-XRT afterglow detection
  75. GRB 230911C: Swift-XRT refined Analysis
  76. GRB 230906A: Chandra detection of the X-ray afterglow
  77. GRB 230906A: Swift/UVOT Upper Limits
  78. GRB 230906A: Swift-XRT observations
  79. GRB 230812B: Chandra late-time detection of the X-ray afterglow
  80. GRB 230903A: Swift-XRT refined Analysis
  81. GRB 230827B: Swift-XRT afterglow detection
  82. GRB 230826A: Swift-XRT refined Analysis
  83. GRB 230824B: AstroSat CZTI detection
  84. GRB 230818A: Swift-XRT refined Analysis
  85. GRB 230816A: Swift-XRT refined Analysis
  86. GRB230815A: Swift/UVOT upper limits
  87. GRB 230815A: Swift-XRT refined Analysis
  88. GRB 230812B: Swift-XRT afterglow detection
  89. GRB 230812B: Improved Swift/XRT localization
  90. GRB 230805B: Swift-XRT refined Analysis
  91. GRB 230802A: Swift-XRT refined Analysis
  92. GRB 230728A: Swift-XRT refined Analysis
  93. GRB 230723B: Swift-XRT refined Analysis
  94. Swift-XRT position for GRB 230723B
  95. IceCube-230707A: No candidates detected by Swift-XRT
  96. GRB 230707A: Swift-XRT observations
  97. GRB 230628E: Swift-XRT refined Analysis
  98. GRB 230623A: Swift-XRT observations
  99. GRB 230622A: Swift-XRT refined Analysis
  100. GRB 230618A: Swift-XRT refined Analysis

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