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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"

6403 results found.

  1. GRB 240910A: SVOM/GRM observation
  2. GRB 240905B: Fermi GBM Observation
  3. EP240908a: TRT optical upper limit
  4. EP240908a: EP detection of a fast X-ray transient
  5. GRB 240905B: Swift-XRT observations
  6. GRB 240905B: Fermi-LAT detection
  7. GRB 240905E: NOT optical upper limits
  8. GRB 240905E: Swift-XRT refined Analysis
  9. GRB 240905E: SAO RAS optical upper limit
  10. GRB 240825A: Swift-BAT refined analysis
  11. GRB 240828A: SAO RAS optical observations
  12. GRB 240828A: Fermi GBM Observation
  13. GRB 240828A: Swift-XRT afterglow detection
  14. GRB 240825A: further SAO RAS optical observations
  15. GRB 240825A: iTelescope optical observations
  16. GRB 240828B: Swift-XRT afterglow detection
  17. GRB 240828A: Fermi-LAT detection
  18. GRB 240821A: the second and third EP-FXT follow-up observations and afterglow candidates
  19. GRB 240819A: Swift afterglow confirmation
  20. Konus-Wind detection of GRB 240825A (bright/long)
  21. GRB 240825A: Fermi GBM Observation
  22. GRB 240825A: Swift-XRT refined Analysis
  23. GRB 240825A: Fermi-LAT detection
  24. GRB 240824B: Fermi GBM Observation
  25. GRB 240824B: Swift-XRT afterglow detection
  26. GRB 240824A: Swift-XRT observations
  27. GRB 240821A: Swift/UVOT observations of the XRT sources.
  28. GRB 240821A: Swift-XRT observations
  29. GECAM-B observation of a short burst from SGR 1E 1841-045 / Kes 73
  30. GRB 240821A: Fermi GBM Observation
  31. GRB 240821A: EP-FXT follow-up observation and afterglow candidates
  32. GRB 240819A: Swift-XRT observations
  33. EP240820a: EP detection of a fast X-ray transient
  34. GRB 240819A: X-ray follow-up observation with EP-FXT
  35. EP240816b: TRT optical upper limit
  36. EP240802a: Kinder optical, SWIFT-UVOT, and SWIFT-XRT upper limits 6 days after the WXT detection
  37. Konus-Wind detection of GRB 240811A
  38. GRB 240811A: Swift-XRT refined Analysis
  39. Konus-Wind detection of GRB 240809A
  40. Konus-Wind detection of GRB 240807A (a counterpart of EP240807a)
  41. Fermi-LAT gamma-ray observations of IceCube-240808A
  42. GRB 240809A: GIT afterglow observations
  43. GRB 240809A: Tentative redshift from NOT
  44. GRB 240809A: Swift-XRT refined Analysis
  45. GRB 240809A: JinShan optical observations
  46. The EP-WXT trigger 01709018832 on August 7th is likely a flaring star
  47. EP240806a: Gemini North-GMOS spectroscopic redshift of z = 2.818
  48. EP240804a (GRB 240804B): NOT optical observations
  49. EP240806a: LCOGT optical counterpart detection
  50. GRB240805A: Fermi GBM Observation
  51. Konus-Wind detection of GRB 240804B (a counterpart of EP240804a)
  52. GRB 240805B: Swift-XRT refined Analysis
  53. GRB 240805A: Swift-XRT refined Analysis
  54. GRB 240805A: Fermi-LAT detection
  55. EP240804a: LCOGT optical counterpart detection
  56. EP240802a: Time coincidence with GRB 240802A and optical upper limits with Kinder observations
  57. EP240801a: further SAO RAS optical observations
  58. EP240801a: SAO RAS optical observations
  59. EP240801a: follow-up observation with LCOGT
  60. EP240801a: Kinder follow-up observations of the candidate counterpart
  61. EP240801a: TRT optical counterpart detection
  62. GRB 240730A: Swift-XRT refined Analysis
  63. GRB 240715A: Swift-XRT afterglow detection
  64. GRB 240730A: Swift detection of a burst
  65. GRB 240727B: Swift-XRT observations
  66. GRB 240727A: Swift-XRT refined Analysis
  67. GRB 240727B: Fermi GBM Observation
  68. GRB 240727A: TRT optical afterglow detection
  69. Fermi-LAT gamma-ray observations of IceCube-240725A
  70. Fermi-LAT gamma-ray observations of IceCube-240721A
  71. GRB 240720A: Fermi GBM observation
  72. GRB 240718A: Fermi GBM Observation
  73. GRB 240718A: Fermi-LAT Detection
  74. IceCube-Cascade 240714A: X-ray follow-up observation with EP-FXT
  75. Fermi-LAT gamma-ray observations of IceCube-cascade-240714A
  76. GRB 240715A: Swift/UVOT observations of the XRT sources.
  77. GRB 240715A: Swift-XRT observations
  78. GRB240713A: Swift/UVOT Upper LImits
  79. GRB 240715A: GECAM-C detection of a short burst
  80. GRB 240713A: Swift-XRT observations
  81. GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
  82. GRB 240712A: Swift-XRT refined Analysis
  83. GRB 240715A: Fermi GBM Observation
  84. The EP-WXT source triggered on July 14th is likely a flaring star
  85. GRB 240713A: NOT optical upper limits on three EP/FXT candidates
  86. GRB240713A: X-ray follow-up observation with EP-FXT
  87. GRB 240713B: AstroSat CZTI detection of a long burst
  88. GRB240713A: Optical upper limit with Kinder observations
  89. EP240708a: NOT optical observations
  90. EP240708a: Optical upper limits with Kinder observations
  91. EP240703c: Kinder optical follow-up and Swift XRT observations
  92. EP240703a: Kinder optical follow-up observations
  93. EP240703c: EP-WXT detection of an X-ray transient
  94. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  95. EP240703a: EP-WXT detection of a fast X-ray transient
  96. Konus-Wind detection of GRB 240619A
  97. GRB 240625A: Fermi GBM Observation
  98. EP240625a: EP-WXT detection of a fast X-ray transient
  99. GRB240624A: Fermi GBM Observation
  100. X-ray transient EP240618a: Fermi/GBM non-detection

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