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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').
  1. GRB 240718A: SVOM/GRM observation
  2. GRB 240718A: BALROG localization (Fermi Trigger 742976945 / GRB 240718270)
  3. GRB 240718A: Fermi GBM Final Real-time Localization
  4. GRB 240712A: Swift-BAT refined analysis
  5. GRB 240716A: GECAM-B detection of a long burst
  6. SVOM/GRM In-Flight Trigger of GRB 240716A
  7. IceCube-Cascade 240714A: X-ray follow-up observation with EP-FXT
  8. GRB 240713A: 2.2m CAHA optical limit
  9. Fermi-LAT gamma-ray observations of IceCube-cascade-240714A
  10. GRB 240715A: Swift/UVOT observations of the XRT sources.
  11. GRB 240715A: Swift-XRT observations
  12. GRB240713A: Swift/UVOT Upper LImits
  13. EP240708a: X-ray follow-up observations with Swift/XRT
  14. GRB 240715A: GECAM-C detection of a short burst
  15. Konus-Wind detection of GRB 240715A
  16. LIGO/Virgo/KAGRA S240716b: Updated Sky localization
  17. GRB 240713A: Swift-XRT observations
  18. GRB 240715A: TRT optical upper limit on one Swift/XRT candidate
  19. GRB 240712A: Swift-XRT refined Analysis
  20. SVOM/GRM In-Flight Trigger of GRB 240715A
  21. GRB 240713A: LAST optical upper limit
  22. LIGO/Virgo/KAGRA S240716b: Identification of a GW compact binary merger candidate
  23. GRB 240715A: Swift ToO observations
  24. Fermi GRB 240715A: Global MASTER-Net observations report
  25. GRB 240713A: optical upper limits from the INAF Asiago Observatory
  26. GRB 240715A: Fermi GBM Observation
  27. GRB 240712A ATCA radio observations
  28. GRB240715A: GRANDMA Optical Upper Limits
  29. IPN triangulation of GRB 240715A (short)
  30. GW s240422ed: Swift UVOT follow-up
  31. GRB 240712A: Swift/UVOT Upper Limits
  32. EP-WXT flaring star and the optical flaring activity during its decay phase
  33. JinShan confirmation of the EP-WXT source triggered on July 14th due to a flaring star
  34. The EP-WXT source triggered on July 14th is likely a flaring star
  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 (duplicate submission of GCN 36859)
  42. GRB240713A: X-ray follow-up observation with EP-FXT
  43. GRB 240713B: AstroSat CZTI detection of a long burst
  44. GRB240713A: Optical upper limit with Kinder observations
  45. Fermi Sub-threshold Observation of GRB240713A
  46. GRB240713A: TAROT and GRANDMA Observations of SVOM/ECLAIRs GRB240713A
  47. GRB240713A : The first probable GRB Located on-Board SVOM by ECLAIRs
  48. Fermi Gamma-ray Burst Monitor trigger 742413075/240711744 is not a GRB
  49. EP240708a: GSP optical upper limit
  50. GRB 240712A: Swift detection of a burst
  51. LIGO/Virgo/KAGRA S240711cm: Coverage and upper limits from MAXI/GSC observations
  52. GRB 240711A: Fermi GBM Final Real-time Localization
  53. Fermi trigger No 742405878: Global MASTER-Net observations report
  54. LIGO/Virgo/KAGRA S240627by: Updated Sky localization and EM Bright Classification
  55. Fermi trigger No 742317942: Global MASTER-Net observations report
  56. EP240708a: KAIT optical upper limit
  57. Fermi GRB 240710A: Global MASTER-Net observations report
  58. GRB 240710A: Fermi GBM Final Real-time Localization
  59. EP240708a: NOT optical observations
  60. EP240708a: SVOM/C-GFT optical upper limit
  61. EP240708a: X-ray follow-up observations with EP/FXT and Swift/XRT
  62. EP240708a: Optical upper limits with Kinder observations
  63. EP240708a: EP-WXT detection of a fast X-ray transient
  64. LIGO/Virgo S240615dg: Swift XRT observations, 28 futher X-ray sources
  65. EP240703b: GSP optical upper limit
  66. Fermi Gamma-ray Burst Monitor trigger 741911057/240705933 is not a GRB
  67. GRB 240705A: Fermi GBM Final Real-time Localization
  68. EP240703b: TRT optical upper limits
  69. EP240703a: TRT further optical observation
  70. EP240702a: TRT optical upper limits
  71. Konus-Wind detection of GRB 240627A
  72. IPN triangulation of GRB 240628B (short)
  73. LIGO/Virgo/KAGRA S240705at: Updated Sky localization
  74. EP240703a and EP240703b: Swift/XRT upper limits
  75. LIGO/Virgo/KAGRA S240705at: Identification of a GW compact binary merger candidate
  76. EP240703a: KAIT optical upper limit
  77. EP240703a: BTA observations
  78. EP240703c: Kinder optical follow-up and Swift XRT observations
  79. EP240703a: BOOTES-3 optical upper limit
  80. EP240703a: Liverpool Telescope optical follow-up observations
  81. EP240703a/GRB 240703A: TRT optical candidate likely not real
  82. EP240703a: Kinder optical follow-up observations
  83. EP240703c: EP-WXT detection of an X-ray transient
  84. LIGO/Virgo/KAGRA S240703ad: Updated Sky localization
  85. LIGO/Virgo/KAGRA S240703ad: Identification of a GW compact binary merger candidate
  86. EP240703a/GRB 240703A: TRT and JinShan decaying optical afterglow candidate
  87. IPN triangulation of GRB 240627A
  88. GRB 240619A: Host galaxy redshift from VLT/X-shooter
  89. LIGO/Virgo/KAGRA S240422ed: Updated significance estimate
  90. The first three GRBs detected by SVOM: X-ray Upper Limits from EP-WXT
  91. EP240703b: EP-WXT detection of a fast X-ray transient
  92. Konus-Wind detection of GRB 240703A (a counterpart of EP240703a)
  93. EP240702a: Swift/XRT upper limit
  94. EP240703a: EP-WXT detection of a fast X-ray transient
  95. EP240702a: GSP optical upper limit
  96. The first three GRBs detected by SVOM: GRB 240627B, GRB 240629A and GRB 240702A
  97. GRB 240702A: BALROG localization (Fermi Trigger / GRB 240702885)
  98. Fermi GRB 240702A: Global MASTER-Net observations report
  99. GRB 240702A: Fermi GBM Final Real-time Localization
  100. EP240702a: EP-WXT detection of a fast X-ray transient

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