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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. GRB 240713A: optical upper limits from the INAF Asiago Observatory
  2. GRB 240715A: Fermi GBM Observation
  3. GRB 240712A ATCA radio observations
  4. GRB240715A: GRANDMA Optical Upper Limits
  5. IPN triangulation of GRB 240715A (short)
  6. GW s240422ed: Swift UVOT follow-up
  7. GRB 240712A: Swift/UVOT Upper Limits
  8. EP-WXT flaring star and the optical flaring activity during its decay phase
  9. JinShan confirmation of the EP-WXT source triggered on July 14th due to a flaring star
  10. The EP-WXT source triggered on July 14th is likely a flaring star
  11. GRB 240715A: Fermi GBM Final Real-time Localization
  12. GRB 240713A: Tiled Swift observations
  13. GRB 240713A: J-band upper limit from WINTER
  14. GRB 240713A: NOT optical upper limits on three EP/FXT candidates
  15. GRB 240713A: JinShan optical upper limits
  16. GRB 240713A: OHP/T120 optical upper limit
  17. GRB240713A: X-ray follow-up observation with EP-FXT (duplicate submission of GCN 36859)
  18. GRB240713A: X-ray follow-up observation with EP-FXT
  19. GRB 240713B: AstroSat CZTI detection of a long burst
  20. GRB240713A: Optical upper limit with Kinder observations
  21. Fermi Sub-threshold Observation of GRB240713A
  22. GRB240713A: TAROT and GRANDMA Observations of SVOM/ECLAIRs GRB240713A
  23. GRB240713A : The first probable GRB Located on-Board SVOM by ECLAIRs
  24. Fermi Gamma-ray Burst Monitor trigger 742413075/240711744 is not a GRB
  25. EP240708a: GSP optical upper limit
  26. GRB 240712A: Swift detection of a burst
  27. LIGO/Virgo/KAGRA S240711cm: Coverage and upper limits from MAXI/GSC observations
  28. GRB 240711A: Fermi GBM Final Real-time Localization
  29. Fermi trigger No 742405878: Global MASTER-Net observations report
  30. LIGO/Virgo/KAGRA S240627by: Updated Sky localization and EM Bright Classification
  31. Fermi trigger No 742317942: Global MASTER-Net observations report
  32. EP240708a: KAIT optical upper limit
  33. Fermi GRB 240710A: Global MASTER-Net observations report
  34. GRB 240710A: Fermi GBM Final Real-time Localization
  35. EP240708a: NOT optical observations
  36. EP240708a: SVOM/C-GFT optical upper limit
  37. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  38. EP240708a: Optical upper limits with Kinder observations
  39. EP240708a: EP-WXT detection of a fast X-ray transient
  40. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  41. EP240703b: GSP optical upper limit
  42. Fermi Gamma-ray Burst Monitor trigger 741911057/240705933 is not a GRB
  43. GRB 240705A: Fermi GBM Final Real-time Localization
  44. EP240703b: TRT optical upper limits
  45. EP240703a: TRT further optical observation
  46. EP240702a: TRT optical upper limits
  47. Konus-Wind detection of GRB 240627A
  48. IPN triangulation of GRB 240628B (short)
  49. LIGO/Virgo/KAGRA S240705at: Updated Sky localization
  50. EP240703a and EP240703b: Swift/XRT upper limits
  51. LIGO/Virgo/KAGRA S240705at: Identification of a GW compact binary merger candidate
  52. EP240703a: KAIT optical upper limit
  53. EP240703a: BTA observations
  54. EP240703c: Kinder optical follow-up and Swift XRT observations
  55. EP240703a: BOOTES-3 optical upper limit
  56. EP240703a: Liverpool Telescope optical follow-up observations
  57. EP240703a/GRB 240703A: TRT optical candidate likely not real
  58. EP240703a: Kinder optical follow-up observations
  59. EP240703c: EP-WXT detection of an X-ray transient
  60. LIGO/Virgo/KAGRA S240703ad: Updated Sky localization
  61. LIGO/Virgo/KAGRA S240703ad: Identification of a GW compact binary merger candidate
  62. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  63. IPN triangulation of GRB 240627A
  64. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  65. LIGO/Virgo/KAGRA S240422ed: Updated significance estimate
  66. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  67. EP240703b: EP-WXT detection of a fast X-ray transient
  68. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  69. EP240702a: Swift/XRT upper limit
  70. EP240703a: EP-WXT detection of a fast X-ray transient
  71. EP240702a: GSP optical upper limit
  72. The first three GRBs detected by SVOM: GRB 240627B, GRB 240629A and GRB 240702A
  73. GRB 240702A: BALROG localization (Fermi Trigger / GRB 240702885)
  74. Fermi GRB 240702A: Global MASTER-Net observations report
  75. GRB 240702A: Fermi GBM Final Real-time Localization
  76. EP240702a: EP-WXT detection of a fast X-ray transient
  77. LIGO/Virgo/KAGRA S240627by: Upper limits from Swift/BAT-GUANO
  78. Fermi Gamma-ray Burst Monitor trigger 741448122/240630575 is not a GRB
  79. GRB 240627A: CALET Gamma-Ray Burst Monitor detection
  80. Fermi trigger No 741448122: Global MASTER-Net observations report
  81. LIGO/Virgo/KAGRA S240630t: Updated Sky localization
  82. LIGO/Virgo/KAGRA S240629by: Updated Sky localization
  83. LIGO/Virgo/KAGRA S240630t: Identification of a GW compact binary merger candidate
  84. LIGO/Virgo/KAGRA S240629by: Upper limits from Fermi-GBM Observations
  85. LIGO/Virgo/KAGRA S240629by: Coverage and upper limits from MAXI/GSC observations
  86. Fermi trigger No 741356809: Global MASTER-Net observations report
  87. Fermi GRB 240629A: Global MASTER-Net observations report
  88. Fermi Gamma-ray Burst Monitor trigger 741362867/240629589 is not a GRB
  89. Fermi Gamma-ray Burst Monitor trigger 741288821/240628732 is not a GRB
  90. GRB 240629A: BALROG localization (Fermi Trigger 741372837 / GRB 240629704)
  91. GRB 240629A: Fermi GBM Final Real-time Localization
  92. Fermi Gamma-ray Burst Monitor trigger 741356809/240629519 is not a GRB
  93. LIGO/Virgo/KAGRA S240629by: Identification of a GW compact binary merger candidate
  94. Fermi trigger No 741296200: Global MASTER-Net observations report
  95. Fermi trigger No 741251380: Global MASTER-Net observations report
  96. IPN triangulation of GRB 240619C
  97. IceCube-Cascade 240626A: Upper limits from a search for additional neutrino events in IceCube
  98. GRB 240628A: BALROG localization (Fermi Trigger 741288821 / GRB 240628732)
  99. GRB 240627A: NuSTAR Detection of the long GRB
  100. GRB 240615A: SAI CMO J- band observations

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