Skip to main content
New Announcement Feature, Code of Conduct, Circular Revisions. See news and announcements

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').

2808 results found.

  1. GRB 230628E: Swift-XRT refined Analysis
  2. GRB 230623A: Swift-XRT observations
  3. GRB 230622A: Swift-XRT refined Analysis
  4. GRB 230618A: Swift-XRT refined Analysis
  5. GRB 230616A: Swift-XRT observations
  6. GRB 230506B: Chandra localization of the X-ray afterglow
  7. GRB 230606A: Swift-XRT refined Analysis
  8. LIGO/Virgo S230518h: Swift XRT observations, 8 X-ray sources
  9. GRB 230512A: Swift-XRT observations
  10. GRB 230510A: Swift-XRT refined Analysis
  11. GRB 230506C: Swift-XRT refined Analysis
  12. GRB 230506C: Swift/UVOT Upper Limits
  13. GRB 230506B: Swift-XRT refined Analysis
  14. GRB 230506C: Swift-XRT analysis
  15. GRB 230427A: Swift-XRT refined Analysis
  16. GRB 230423A: Swift-XRT refined Analysis
  17. GRB 230420A: Swift-XRT refined Analysis
  18. GRB 230414B: Swift-XRT refined Analysis
  19. GRB 230409B: Swift-XRT refined Analysis
  20. GRB 230405B: Swift-XRT refined Analysis
  21. GRB 230307A: Chandra late-time detection of the X-ray afterglow
  22. GRB 230328B: 3.6m DOT multiband optical observation
  23. GRB 230328B: Swift-XRT refined Analysis
  24. GRB 230325A: Swift-XRT refined Analysis
  25. GRB 230322B: Swift-XRT refined Analysis
  26. GRB 230307A: INTEGRAL upper limit on Hard X-ray afterglow
  27. GRB 230307A: Swift/UVOT detection
  28. GRB 230307A: Swift-XRT afterglow detection
  29. GRB 230307A: Swift/BAT upper limits on the early afterglow
  30. GRB 230307A: Swift-XRT observations
  31. GRB 230228A: Swift-XRT refined Analysis
  32. GRB 230217A: Swift/UVOT Upper Limits
  33. GRB 230217A: Swift-XRT afterglow detection
  34. GRB 230217A: Swift-XRT observations
  35. GRB 230216A: Swift-XRT refined Analysis
  36. Swift Trigger 1153670 is probably not a GRB
  37. GRB 221009A: Continued Swift Observations
  38. GRB 230204B: Swift/UVOT Upper Limits
  39. GRB 230204B: Swift-XRT afterglow detection
  40. GRB 230205A: Swift-XRT refined Analysis
  41. GRB 230204A: Swift-XRT refined Analysis
  42. GRB 230123A: Swift-XRT refined Analysis
  43. GRB 230116C: Swift-XRT observations
  44. GRB 230116D: Swift-XRT refined Analysis
  45. GRB 221231A: Swift-XRT afterglow detection
  46. GRB 221231A: Swift-XRT observations
  47. GRB 221226B: Swift-XRT refined Analysis
  48. GRB 221216A: Swift-XRT refined Analysis
  49. GRB 221215A: Swift-XRT observations
  50. GRB 221206B: Swift-XRT observations
  51. GRB 221202A: Swift-XRT refined Analysis
  52. GRB 221201A: Swift-XRT refined Analysis
  53. GRB 221120A: Swift-XRT refined Analysis
  54. GRB 221119A: Fermi-LAT detection
  55. GRB 221110A: Swift-XRT refined Analysis
  56. GRB 221028A: Swift-XRT refined Analysis
  57. GRB 221027B: Swift-XRT refined Analysis
  58. GRB 221022A: Swift-XRT observations
  59. GRB 221024A: Swift-XRT refined Analysis
  60. GRB 221017A: Swift-XRT observations
  61. GRB 221009A: Second epoch of NuSTAR data
  62. GRB 221016A: Swift-XRT refined Analysis
  63. MAXI/GSC refined analysis of the bright X-ray afterglow of GRB 221009A/Swift J1913.1+1946
  64. GRB 221009A: IXPE preliminary upper limits of X-ray polarization
  65. GRB 221006A: Swift-XRT afterglow detection
  66. GRB 221009A: NuSTAR Detection
  67. GRB221009A: INTEGRAL detection of Hard X-ray emission up to 38 hours after trigger
  68. GRB 221009A: Continued Swift/XRT observations
  69. GRB 221009A: Swift-XRT refined Analysis
  70. GRB 221008A: Swift-XRT observations
  71. GRB 221006A: Swift-XRT observations
  72. GRB 220930A: Swift-XRT refined Analysis
  73. GRB 220921A: Swift-XRT Observations
  74. GRB 220909A: Swift-XRT observations
  75. GRB 220831A: Gemini-South Infrared Observations
  76. GRB 220907A: Swift-XRT refined Analysis
  77. GRB 220907A: Swift-XRT position
  78. GRB 220831A: Swift-UVOT Upper Limits
  79. GRB 220831A: Swift-XRT observations
  80. GRB 220826A: Swift-XRT refined Analysis
  81. GRB 220810A: Further Swift-XRT observations
  82. GRB 220813A: Swift-XRT refined Analysis
  83. GRB 220810A: Swift-XRT observations
  84. GRB 220730A: Swift-XRT afterglow detection
  85. GRB 220730A: Swift-XRT observations
  86. GRB 220715B: Swift-XRT refined Analysis
  87. GRB 220714B: Swift-XRT refined Analysis
  88. GRB 220711B: 10.4 m GTC(+EMIR) observations
  89. GRB 220711B: 10.4 m GTC(+EMIR) observations
  90. GRB 220710A: Swift-XRT afterglow detection
  91. GRB 220711B: Swift-XRT refined Analysis
  92. GRB 220708A: Swift-XRT refined Analysis
  93. GRB 220708B: Swift-XRT afterglow detection
  94. GRB 220706A: Swift-XRT refined Analysis
  95. GRB 220701A: Swift-XRT refined Analysis
  96. GRB 220627A: Swift-XRT afterglow detection
  97. Swift XRT observations of WISEA J145820.77+412101.9 / IceCube 220624A
  98. GRB 220611A: X-ray afterglow Chandra sub-arcsecond localization
  99. GRB 220623A: Swift-XRT refined Analysis
  100. GRB 220611A: Continued Gemini Infrared Observations

Advanced

Download all Circulars as a .tar.gz archive:
Questions or comments?
Contact GCN directly.
Have you found a bug in GCN?
Open an issue.
Want to contribute code to GCN?
Get involved on GitHub.

gcn.nasa.gov

A service of the Astrophysics Science Division at NASA Goddard Space Flight Center

Looking for U.S. government information and services? Visit USA.gov