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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').
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"

6094 results found.

  1. GRB 231118A: Swift-XRT refined Analysis
  2. GRB 231117A: Kinder observations with Lulin observatory for AT 2023yba without fading in r band
  3. GRB 231117A: GIT optical follow-up
  4. GRB 231117A: afterglow candidate detection from Kinder observations with Lulin observatory
  5. MAGIC observation of GRB 231115A, a possible magnetar giant flare
  6. GRB 231115A: NuSTAR Follow-Up Observations
  7. GRB 231115A: Swift-XRT and Swift-UVOT observations
  8. GRB 231115A: archival Chandra X-ray observations
  9. GRB 231115A: Kinder observations with Lulin observatory
  10. GRB 231115A: Fermi Observations of a probable Magnetar Giant Flare from M82
  11. LIGO/Virgo/KAGRA S231113bw: GROWTH-India coverage and upper limits
  12. GECAM-B observation of a short burst from SGR J1555-5402
  13. LIGO/Virgo S231113bw: upper limits from AGILE/MCAL
  14. GRB 231110A: Swift-UVOT Upper Limits
  15. GRB 231111A: Swift-XRT refined Analysis
  16. GRB 231110A: SAO RAS optical observations
  17. GRB 231110A: Swift-XRT afterglow detection
  18. GRB231111A: GIT confirmation of the optical afterglow
  19. Fermi-LAT gamma-ray observations of IceCube-231103A
  20. GRB 231104A: Fermi GBM Observation
  21. GRB 231104A: Swift-XRT refined Analysis
  22. GRB 231104A: Fermi-LAT detection
  23. Fermi-LAT gamma-ray observations of IceCube-231027A
  24. GRB 231030B: Fermi GBM Detection
  25. GRB 231028A: Fermi GBM Detection
  26. GRB 231025A: Fermi GBM Observation
  27. GRB 231024A: LCOGT and ZTF detections of the GOTO optical counterpart candidate
  28. GRB 231020A: Fermi GBM Detection
  29. GRB 231012A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
  30. GRB231017A: GROWTH-India upper limits on the optical afterglow
  31. GRB 231018A: Fermi GBM Detection
  32. GRB 231017A: Fermi GBM Detection
  33. GRB 231017A: Swift-XRT observations
  34. Fermi-LAT gamma-ray observations of IceCube-231014A
  35. IceCube-231004A: No significant detection in HAWC
  36. Fermi-LAT gamma-ray observations of IceCube-231004A
  37. Fermi GBM Statement for Trigger 716527670/230916144
  38. AT 2023sva: NOT observations of the ZTF candidate afterglow
  39. GRB 230915A: Fermi GBM observation
  40. GRB 230911A: Fermi GBM Observation
  41. Fermi-LAT gamma-ray observations of IceCube-230914A
  42. GRB 230906A: optical counterpart
  43. GRB 230911A: Swift-XRT afterglow detection
  44. GRB 230913A: Fermi GBM Observation
  45. GRB 230911C: Swift-XRT refined Analysis
  46. GRB 230906A: Chandra detection of the X-ray afterglow
  47. GRB 230911D: Fermi GBM observation
  48. GRB 230911D: Fermi-LAT detection
  49. GRB 230906A: BlackGEM upper limits
  50. GRB 230906A: Swift/UVOT Upper Limits
  51. GRB 230906A: Swift-XRT observations
  52. GRB 230812B: Chandra late-time detection of the X-ray afterglow
  53. GRB 230903A: Swift-XRT refined Analysis
  54. GRB 230903A: Fermi GBM detection
  55. GRB 230827B: Swift-XRT afterglow detection
  56. GRB 230827A: Fermi GBM Observation
  57. GRB 230827B / GRB 230827256: Fermi GBM Observation
  58. GRB 230827.256 : GIT optical follow-up of ZTF23abaanxz/AT2023qxj
  59. GRB 230826A: Fermi GBM Observation
  60. GRB 230826A: Swift-XRT refined Analysis
  61. GRB 230822A: Fermi GBM Observation
  62. GRB 230812B: SAO RAS RC-500 and Zeiss-1000 observations
  63. GRB 20230818A: GIT optical upper limit
  64. Konus-Wind detection of GRB 230818A
  65. GRB 230818A: Fermi GBM Observation
  66. GRB 230812B: GIT Confirmation of SN rise
  67. GRB 230812B: SAO RAS Zeiss-1000 observations
  68. GRB 230818A: further SAO RAS Zeiss-1000 observations
  69. GRB 230818A: Swift-XRT refined Analysis
  70. GRB 230818A: SAO RAS Zeiss-1000 observations
  71. Fermi GRB 230818A: Global MASTER-Net observations report
  72. Fermi trigger No 713974668: Global MASTER-Net observations report
  73. GRB 230812B: SAO RAS observations, possible re-brightening
  74. GRB 230812B: SAO RAS optical observations
  75. GRB 230816A: Swift-XRT refined Analysis
  76. GRB 230812B: optical photometry from Konkoly
  77. GRB 230812B: SAO RAS optical observations
  78. GRB230816A: Possible host and GIT detection of optical counterpart
  79. GRB 230816A: SAO RAS optical observations
  80. GRB 230815A: Swift-XRT refined Analysis
  81. GRB 230812B: iTelescope optical upper limit
  82. GRB 230812B: continued SAO RAS optical observation
  83. GRB 230815A: Fermi GBM detection
  84. GRB 230812B: Iota Scorpii Observatory, La Spezia, Italy
  85. GRB 230812B: further SAO RAS optical observations
  86. GRB 230812B: Upper limits from a neutrino search with IceCube
  87. GRB 230812B: GIT optical follow-up
  88. GRB 230812B: rest-frame energetics from Konus-Wind observation
  89. GRB 230812B: SAO RAS optical observations
  90. GRB 230812B: Swift-XRT afterglow detection
  91. GRB 230812B: Zwicky Transient Facility Identifies Optical Afterglow Candidate of a Fermi GRB (Trigger 713559497)
  92. GRB 230812B: Improved Swift/XRT localization
  93. GRB 230812B: Fermi-LAT detection
  94. GRB 230808A: Fermi GBM Detection
  95. GRB 230805B: Iota Scorpii Observatory, La Spezia, Italy upper limit
  96. GRB 230805B: Fermi GBM observation
  97. GRB 230805B: Swift-XRT refined Analysis
  98. GRB 230805B: SAO RAS optical observations
  99. GRB 230802A: Fermi GBM observation
  100. GRB 230802A: Swift-XRT refined Analysis

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