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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"
  1. Konus-Wind detection of GRB 240715A
  2. LIGO/Virgo/KAGRA S240716b: Updated Sky localization
  3. GRB 240713A: Swift-XRT observations
  4. GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
  5. GRB 240712A: Swift-XRT refined Analysis
  6. SVOM/GRM In-Flight Trigger of GRB 240715A
  7. GRB 240713A: LAST optical upper limit
  8. LIGO/Virgo/KAGRA S240716b: Identification of a GW compact binary merger candidate
  9. GRB 240715A: Swift ToO observations
  10. Fermi GRB 240715A: Global MASTER-Net observations report
  11. GRB 240713A: optical upper limits from the INAF Asiago Observatory
  12. GRB 240715A: Fermi GBM Observation
  13. GRB 240712A ATCA radio observations
  14. GRB240715A: GRANDMA Optical Upper Limits
  15. IPN triangulation of GRB 240715A (short)
  16. GW s240422ed: Swift UVOT follow-up
  17. GRB 240712A: Swift/UVOT Upper Limits
  18. EP-WXT flaring star and the optical flaring activity during its decay phase
  19. JinShan confirmation of the EP-WXT source triggered on July 14th due to a flaring star
  20. The EP-WXT source triggered on July 14th is likely a flaring star
  21. GRB 240715A: Fermi GBM Final Real-time Localization
  22. GRB 240713A: Tiled Swift observations
  23. GRB 240713A: J-band upper limit from WINTER
  24. GRB 240713A: NOT optical upper limits on three EP/FXT candidates
  25. GRB 240713A: JinShan optical upper limits
  26. GRB 240713A: OHP/T120 optical upper limit
  27. GRB240713A: X-ray follow-up observation with EP-FXT (duplicate submission of GCN 36859)
  28. GRB240713A: X-ray follow-up observation with EP-FXT
  29. GRB 240713B: AstroSat CZTI detection of a long burst
  30. GRB240713A: Optical upper limit with Kinder observations
  31. Fermi Sub-threshold Observation of GRB240713A
  32. GRB240713A: TAROT and GRANDMA Observations of SVOM/ECLAIRs GRB240713A
  33. GRB240713A : The first probable GRB Located on-Board SVOM by ECLAIRs
  34. Fermi Gamma-ray Burst Monitor trigger 742413075/240711744 is not a GRB
  35. EP240708a: GSP optical upper limit
  36. GRB 240712A: Swift detection of a burst
  37. LIGO/Virgo/KAGRA S240711cm: Coverage and upper limits from MAXI/GSC observations
  38. GRB 240711A: Fermi GBM Final Real-time Localization
  39. Fermi trigger No 742405878: Global MASTER-Net observations report
  40. LIGO/Virgo/KAGRA S240627by: Updated Sky localization and EM Bright Classification
  41. Fermi trigger No 742317942: Global MASTER-Net observations report
  42. EP240708a: KAIT optical upper limit
  43. Fermi GRB 240710A: Global MASTER-Net observations report
  44. GRB 240710A: Fermi GBM Final Real-time Localization
  45. EP240708a: NOT optical observations
  46. EP240708a: SVOM/C-GFT optical upper limit
  47. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  48. EP240708a: Optical upper limits with Kinder observations
  49. EP240708a: EP-WXT detection of a fast X-ray transient
  50. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  51. EP240703b: GSP optical upper limit
  52. Fermi Gamma-ray Burst Monitor trigger 741911057/240705933 is not a GRB
  53. GRB 240705A: Fermi GBM Final Real-time Localization
  54. EP240703b: TRT optical upper limits
  55. EP240703a: TRT further optical observation
  56. EP240702a: TRT optical upper limits
  57. Konus-Wind detection of GRB 240627A
  58. IPN triangulation of GRB 240628B (short)
  59. LIGO/Virgo/KAGRA S240705at: Updated Sky localization
  60. EP240703a and EP240703b: Swift/XRT upper limits
  61. LIGO/Virgo/KAGRA S240705at: Identification of a GW compact binary merger candidate
  62. EP240703a: KAIT optical upper limit
  63. EP240703a: BTA observations
  64. EP240703c: Kinder optical follow-up and Swift XRT observations
  65. EP240703a: BOOTES-3 optical upper limit
  66. EP240703a: Liverpool Telescope optical follow-up observations
  67. EP240703a/GRB 240703A: TRT optical candidate likely not real
  68. EP240703a: Kinder optical follow-up observations
  69. EP240703c: EP-WXT detection of an X-ray transient
  70. LIGO/Virgo/KAGRA S240703ad: Updated Sky localization
  71. LIGO/Virgo/KAGRA S240703ad: Identification of a GW compact binary merger candidate
  72. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  73. IPN triangulation of GRB 240627A
  74. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  75. LIGO/Virgo/KAGRA S240422ed: Updated significance estimate
  76. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  77. EP240703b: EP-WXT detection of a fast X-ray transient
  78. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  79. EP240702a: Swift/XRT upper limit
  80. EP240703a: EP-WXT detection of a fast X-ray transient
  81. EP240702a: GSP optical upper limit
  82. The first three GRBs detected by SVOM: GRB 240627B, GRB 240629A and GRB 240702A
  83. GRB 240702A: BALROG localization (Fermi Trigger / GRB 240702885)
  84. Fermi GRB 240702A: Global MASTER-Net observations report
  85. GRB 240702A: Fermi GBM Final Real-time Localization
  86. EP240702a: EP-WXT detection of a fast X-ray transient
  87. LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
  88. Fermi Gamma-ray Burst Monitor trigger 741448122/240630575 is not a GRB
  89. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  90. Fermi trigger No 741448122: Global MASTER-Net observations report
  91. LIGO/Virgo/KAGRA S240630t: Updated Sky localization
  92. LIGO/Virgo/KAGRA S240629by: Updated Sky localization
  93. LIGO/Virgo/KAGRA S240630t: Identification of a GW compact binary merger candidate
  94. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  95. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  96. Fermi trigger No 741356809: Global MASTER-Net observations report
  97. Fermi GRB 240629A: Global MASTER-Net observations report
  98. Fermi Gamma-ray Burst Monitor trigger 741362867/240629589 is not a GRB
  99. Fermi Gamma-ray Burst Monitor trigger 741288821/240628732 is not a GRB
  100. GRB 240629A: BALROG localization (Fermi Trigger 741372837 / GRB 240629704)

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