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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"

37553 results found.

  1. GRB 240720A: AstroSat CZTI detection
  2. GRB 240720A: Fermi GBM observation
  3. GRB 240720A: Swift detection of a burst
  4. Konus-Wind detection of GRB 240718A
  5. GRB 240713A: SVOM/GRM observation
  6. Fermi GRB 240718A: Global MASTER-Net observations report
  7. GRB 240718A: Fermi GBM Observation
  8. GRB 240718A: Fermi-LAT Detection
  9. GRB 240718A: SVOM/GRM observation
  10. GRB 240718A: BALROG localization (Fermi Trigger 742976945 / GRB 240718270)
  11. GRB 240718A: Fermi GBM Final Real-time Localization
  12. GRB 240712A: Swift-BAT refined analysis
  13. GRB 240716A: GECAM-B detection of a long burst
  14. SVOM/GRM In-Flight Trigger of GRB 240716A
  15. GRB 240713A: 2.2m CAHA optical limit
  16. Fermi-LAT gamma-ray observations of IceCube-cascade-240714A
  17. GRB 240715A: Swift/UVOT observations of the XRT sources.
  18. GRB 240715A: Swift-XRT observations
  19. GRB240713A: Swift/UVOT Upper LImits
  20. GRB 240715A: GECAM-C detection of a short burst
  21. Konus-Wind detection of GRB 240715A
  22. GRB 240713A: Swift-XRT observations
  23. GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
  24. GRB 240712A: Swift-XRT refined Analysis
  25. SVOM/GRM In-Flight Trigger of GRB 240715A
  26. GRB 240713A: LAST optical upper limit
  27. GRB 240715A: Swift ToO observations
  28. Fermi GRB 240715A: Global MASTER-Net observations report
  29. GRB 240713A: optical upper limits from the INAF Asiago Observatory
  30. GRB 240715A: Fermi GBM Observation
  31. GRB 240712A ATCA radio observations
  32. GRB240715A: GRANDMA Optical Upper Limits
  33. IPN triangulation of GRB 240715A (short)
  34. GRB 240712A: Swift/UVOT Upper Limits
  35. GRB 240715A: Fermi GBM Final Real-time Localization
  36. GRB 240713A: Tiled Swift observations
  37. GRB 240713A: J-band upper limit from WINTER
  38. GRB 240713A: NOT optical upper limits on three EP/FXT candidates
  39. GRB 240713A: JinShan optical upper limits
  40. GRB 240713A: OHP/T120 optical upper limit
  41. GRB240713A: X-ray follow-up observation with EP-FXT
  42. GRB 240713B: AstroSat CZTI detection of a long burst
  43. Fermi Sub-threshold Observation of GRB240713A
  44. GRB240713A : The first probable GRB Located on-Board SVOM by ECLAIRs
  45. Fermi Gamma-ray Burst Monitor trigger 742413075/240711744 is not a GRB
  46. GRB 240712A: Swift detection of a burst
  47. GRB 240711A: Fermi GBM Final Real-time Localization
  48. Fermi trigger No 742405878: Global MASTER-Net observations report
  49. Fermi trigger No 742317942: Global MASTER-Net observations report
  50. EP240708a: KAIT optical upper limit
  51. Fermi GRB 240710A: Global MASTER-Net observations report
  52. GRB 240710A: Fermi GBM Final Real-time Localization
  53. EP240708a: SVOM/C-GFT optical upper limit
  54. Fermi Gamma-ray Burst Monitor trigger 741911057/240705933 is not a GRB
  55. GRB 240705A: Fermi GBM Final Real-time Localization
  56. Konus-Wind detection of GRB 240627A
  57. IPN triangulation of GRB 240628B (short)
  58. EP240703a: KAIT optical upper limit
  59. EP240703a: BTA observations
  60. EP240703a/GRB 240703A: TRT optical candidate likely not real
  61. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  62. IPN triangulation of GRB 240627A
  63. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  64. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  65. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  66. The first three GRBs detected by SVOM: GRB 240627B, GRB 240629A and GRB 240702A
  67. GRB 240702A: BALROG localization (Fermi Trigger / GRB 240702885)
  68. Fermi GRB 240702A: Global MASTER-Net observations report
  69. GRB 240702A: Fermi GBM Final Real-time Localization
  70. LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
  71. Fermi Gamma-ray Burst Monitor trigger 741448122/240630575 is not a GRB
  72. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  73. Fermi trigger No 741448122: Global MASTER-Net observations report
  74. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  75. Fermi trigger No 741356809: Global MASTER-Net observations report
  76. Fermi GRB 240629A: Global MASTER-Net observations report
  77. Fermi Gamma-ray Burst Monitor trigger 741362867/240629589 is not a GRB
  78. Fermi Gamma-ray Burst Monitor trigger 741288821/240628732 is not a GRB
  79. GRB 240629A: BALROG localization (Fermi Trigger 741372837 / GRB 240629704)
  80. GRB 240629A: Fermi GBM Final Real-time Localization
  81. Fermi Gamma-ray Burst Monitor trigger 741356809/240629519 is not a GRB
  82. Fermi trigger No 741296200: Global MASTER-Net observations report
  83. Fermi trigger No 741251380: Global MASTER-Net observations report
  84. IPN triangulation of GRB 240619C
  85. GRB 240628A: BALROG localization (Fermi Trigger 741288821 / GRB 240628732)
  86. GRB 240627A: NuSTAR Detection of the long GRB
  87. GRB 240615A: SAI CMO J- band observations
  88. GRB 240627A: AstroSat CZTI detection
  89. Fermi trigger No 741211696: Global MASTER-Net observations report
  90. EP240626a: Montarrenti Observatory optical upper limit
  91. EP240626a: KAIT optical upper limit
  92. GRB 240624A: Swift-BAT refined analysis
  93. Konus-Wind detection of GRB 240619A
  94. Fermi GRB 240625B: Global MASTER-Net observations report
  95. GRB 240624B: CALET Gamma-Ray Burst Monitor detection
  96. GRB 240625B: Fermi GBM Final Real-time Localization
  97. GRB 240625A: Fermi GBM Observation
  98. GRB 240624B: GRBAlpha detection
  99. GRB 240625A: Fermi GBM Final Real-time Localization
  100. GRB240624A: Fermi GBM Observation

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