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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"

6519 results found.

  1. GRB 231214A: Fermi-LAT detection
  2. Fermi-LAT detection of increased gamma-ray activity of blazar PKS 2047+098, located inside the IceCube-231211A error region
  3. GRB 231210B: Swift-XRT refined Analysis
  4. GRB 231205B: 1.3m DFOT Optical upper limit
  5. GRB 231205B: Swift-XRT refined Analysis
  6. Fermi-LAT gamma-ray observations of IceCube-231202A
  7. Fermi-LAT daily aperture light curve of T CrB now available
  8. GRB 231203A: Fermi GBM Observation
  9. GRB 231129C: Swift-XRT afterglow detection
  10. GRB 231129B: Swift-XRT observations
  11. GRB 231129C: Fermi-LAT detection
  12. GRB 231129C: Swift-XRT observations
  13. GRB 231129C: Fermi GBM Observation of a very bright GRB
  14. GRB 231129C: iTelescope likely optical afterglow AT 2023yph discovery
  15. GRB 231129A: Swift-XRT refined Analysis
  16. Fermi-LAT gamma-ray observations of IceCube-231125A
  17. GRB 231123C: Fermi GBM Observation
  18. GRB 231123B: Fermi GBM Observation
  19. GRB 231111A: Optical follow-up observations at Terskol, AbAO, Maidanak, Mondy, Assy
  20. GRB 231115A: XMM-Newton observation
  21. GRB 231117A: Chandra afterglow detection
  22. GRB 231117A: GTC Near-Infrared Observations
  23. GRB 231118B: Fermi GBM observation
  24. GRB 231118A: Fermi GBM observation
  25. GRB 231117A: Swift-XRT refined Analysis
  26. GRB 231118A: Swift-XRT refined Analysis
  27. GRB 231117A: Kinder observations with Lulin observatory for AT 2023yba without fading in r band
  28. GRB 231117A: GIT optical follow-up
  29. GRB 231117A: afterglow candidate detection from Kinder observations with Lulin observatory
  30. MAGIC observation of GRB 231115A, a possible magnetar giant flare
  31. GRB 231115A: NuSTAR Follow-Up Observations
  32. GRB 231115A: Swift-XRT and Swift-UVOT observations
  33. GRB 231115A: archival Chandra X-ray observations
  34. GRB 231115A: Kinder observations with Lulin observatory
  35. GRB 231115A: Fermi Observations of a probable Magnetar Giant Flare from M82
  36. LIGO/Virgo/KAGRA S231113bw: GROWTH-India coverage and upper limits
  37. GECAM-B observation of a short burst from SGR J1555-5402
  38. LIGO/Virgo S231113bw: upper limits from AGILE/MCAL
  39. GRB 231110A: Swift-UVOT Upper Limits
  40. GRB 231111A: Swift-XRT refined Analysis
  41. GRB 231110A: SAO RAS optical observations
  42. GRB 231110A: Swift-XRT afterglow detection
  43. GRB231111A: GIT confirmation of the optical afterglow
  44. Fermi-LAT gamma-ray observations of IceCube-231103A
  45. GRB 231104A: Fermi GBM Observation
  46. GRB 231104A: Swift-XRT refined Analysis
  47. GRB 231104A: Fermi-LAT detection
  48. Fermi-LAT gamma-ray observations of IceCube-231027A
  49. GRB 231030B: Fermi GBM Detection
  50. GRB 231028A: Fermi GBM Detection
  51. GRB 231025A: Fermi GBM Observation
  52. GRB 231024A: LCOGT and ZTF detections of the GOTO optical counterpart candidate
  53. GRB 231020A: Fermi GBM Detection
  54. GRB 231012A: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 705709044)
  55. GRB231017A: GROWTH-India upper limits on the optical afterglow
  56. GRB 231018A: Fermi GBM Detection
  57. GRB 231017A: Fermi GBM Detection
  58. GRB 231017A: Swift-XRT observations
  59. Fermi-LAT gamma-ray observations of IceCube-231014A
  60. IceCube-231004A: No significant detection in HAWC
  61. Fermi-LAT gamma-ray observations of IceCube-231004A
  62. Fermi GBM Statement for Trigger 716527670/230916144
  63. AT 2023sva: NOT observations of the ZTF candidate afterglow
  64. GRB 230915A: Fermi GBM observation
  65. GRB 230911A: Fermi GBM Observation
  66. Fermi-LAT gamma-ray observations of IceCube-230914A
  67. GRB 230906A: optical counterpart
  68. GRB 230911A: Swift-XRT afterglow detection
  69. GRB 230913A: Fermi GBM Observation
  70. GRB 230911C: Swift-XRT refined Analysis
  71. GRB 230906A: Chandra detection of the X-ray afterglow
  72. GRB 230911D: Fermi GBM observation
  73. GRB 230911D: Fermi-LAT detection
  74. GRB 230906A: BlackGEM upper limits
  75. GRB 230906A: Swift/UVOT Upper Limits
  76. GRB 230906A: Swift-XRT observations
  77. GRB 230812B: Chandra late-time detection of the X-ray afterglow
  78. GRB 230903A: Swift-XRT refined Analysis
  79. GRB 230903A: Fermi GBM detection
  80. GRB 230827B: Swift-XRT afterglow detection
  81. GRB 230827A: Fermi GBM Observation
  82. GRB 230827B / GRB 230827256: Fermi GBM Observation
  83. GRB 230827.256 : GIT optical follow-up of ZTF23abaanxz/AT2023qxj
  84. GRB 230826A: Fermi GBM Observation
  85. GRB 230826A: Swift-XRT refined Analysis
  86. GRB 230822A: Fermi GBM Observation
  87. GRB 230812B: SAO RAS RC-500 and Zeiss-1000 observations
  88. GRB 20230818A: GIT optical upper limit
  89. Konus-Wind detection of GRB 230818A
  90. GRB 230818A: Fermi GBM Observation
  91. GRB 230812B: GIT Confirmation of SN rise
  92. GRB 230812B: SAO RAS Zeiss-1000 observations
  93. GRB 230818A: further SAO RAS Zeiss-1000 observations
  94. GRB 230818A: Swift-XRT refined Analysis
  95. GRB 230818A: SAO RAS Zeiss-1000 observations
  96. Fermi GRB 230818A: Global MASTER-Net observations report
  97. Fermi trigger No 713974668: Global MASTER-Net observations report
  98. GRB 230812B: SAO RAS observations, possible re-brightening
  99. GRB 230812B: SAO RAS optical observations
  100. GRB 230816A: Swift-XRT refined Analysis

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