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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').

21220 results found.

  1. Fermi Gamma-ray Burst Monitor trigger 737076431/240510977 is not a GRB
  2. Fermi trigger No 736967879: Global MASTER-Net observations report
  3. EP240506a: Xinglong optical upper limit
  4. Fermi Gamma-ray Burst Monitor trigger 230925241/717313591 is not a GRB
  5. EP240506a: CrAO ZTSH optical upper limit
  6. GRB 240504A: Fermi GBM Observation
  7. Fermi Gamma-ray Burst Monitor trigger 736837160/240508208 is not a GRB
  8. EP240506a: TRT optical upper limit
  9. EP240506a: BOOTES Network optical upper limit
  10. Fermi trigger No 736733320: Global MASTER-Net observations report
  11. EP240506a: Optical upper limit with Kinder observations
  12. IPN triangulation of GRB 240504A
  13. LIGO/Virgo/KAGRA S240422ed: Additional WINTER near-infrared J-band observations
  14. GRB 240504A: Swift/BAT-GUANO detection of a burst outside the coded FOV
  15. Fermi trigger No 736564880: Global MASTER-Net observations report
  16. Fermi trigger No 736461232: Global MASTER-Net observations report
  17. Fermi GRB 240504A: Global MASTER-Net observations report
  18. Fermi trigger No 736472503: Global MASTER-Net observations report
  19. GRB 240504A: BALROG localization (Fermi Trigger 736492377 / GRB 240504217)
  20. GRB 240504A: Fermi GBM Final Real-time Localization
  21. Fermi trigger No 736387941: Global MASTER-Net observations report
  22. LXT 240402A / GRB 240402B: VLT X-shooter redshift of host
  23. GRB 240502A: GOTO optical upper limit
  24. Fermi trigger No 736379109: Global MASTER-Net observations report
  25. GRB 240502A: Fermi GBM Observation
  26. GRB 240502C: GOTO possible optical counterpart candidates
  27. Fermi GRB 240502B: Global MASTER-Net observations report
  28. GRB 240502C: Fermi GBM Final Localization
  29. Fermi GRB 240502A: Global MASTER-Net observations report
  30. GRB 240430A: GRBAlpha detection
  31. GRB 240502B: Fermi GBM Final Real-time Localization
  32. LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet Transient Candidates
  33. Integral GRB240502.23: Global MASTER-Net observations report
  34. GRB 240502A: Fermi GBM Final Real-time Localization
  35. Fermi GRB 240501A: Global MASTER-Net observations report
  36. Fermi trigger No 736197684: Global MASTER-Net observations report
  37. GRB 240426A: VZLUSAT-2 detection
  38. GRB240430A: Fermi GBM Final Localization
  39. GRB 240501A: Fermi GBM Final Real-time Localization
  40. GRB 240408B: VZLUSAT-2 detection
  41. GRB 240407A: VZLUSAT-2 detection
  42. GRB 240429A: Fermi GBM Final Real-time Localization
  43. LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet ToO observations
  44. LIGO/Virgo/KAGRA S240429an: Retraction of GW compact binary merger candidate
  45. Fermi GRB 240428A: Global MASTER-Net observations report
  46. GRB 240428A: Fermi GBM Final Real-time Localization
  47. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility contuinued observations of S240422ed and candidate analysis
  48. LIGO/Virgo/KAGRA S240422ed: 2.5m PRL Telescope follow-up of the Swift/XRT source S240422ed_X190
  49. LIGO/Virgo/KAGRA S240422ed: Upper limits from GECAM Observations
  50. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA and Kilonova-Catcher galaxy targeting observations
  51. GRB 240425A: Fermi GBM Final Real-time Localization
  52. Fermi trigger No 735697285: Global MASTER-Net observations report
  53. GRB 240419B: Swift-BAT refined analysis
  54. GRB 240421B: Swift-BAT refined analysis
  55. LIGO/Virgo/KAGRA S240422ed: Himalayan Chandra Telescope follow-up of the Swift/XRT source S240422ed_X101
  56. LIGO/Virgo/KAGRA S240422ed: No significant counterpart candidates in HAWC observations
  57. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  58. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  59. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  60. LIGO/Virgo/KAGRA S240422ed: Early X-ray Upper Limits from EP-WXT for the LVK Sky Localization Region
  61. LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
  62. GRB 240421B: GRBAlpha detection
  63. IceCube Alert 240424.08: Global MASTER-Net observations report
  64. LIGO/Virgo/KAGRA S240422ed: Potential Candidates from Magellan galaxy-based search
  65. LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search
  66. GRB 240419A: Swift-BAT refined analysis
  67. GRB 240418A: Swift-BAT refined analysis
  68. LIGO/Virgo/KAGRA S240423br: Retraction of GW compact binary merger candidate
  69. LIGO/Virgo/KAGRA S240422ed: WINTER near-infrared J-band observations
  70. LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  71. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility observations and candidates
  72. LIGO/Virgo/KAGRA S240422ed: AstroSat CZTI non-detection and upper limits
  73. LIGO/Virgo/KAGRA S240422ed: Upper limits from Fermi-GBM Observations
  74. LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO
  75. LIGO/Virgo/KAGRA S240422ed: Coverage and upper limits from MAXI/GSC observations
  76. LIGO/Virgo/KAGRA S240422ed: Global MASTER-Net observations report
  77. Fermi trigger No 735470374: Global MASTER-Net observations report
  78. GRB 240414A: LBT optical detection
  79. GRB 240419B : MITSuME Akeno optical upper limits
  80. GRB 240415B: Swift-XRT observations
  81. GRB 240415A: Swift-XRT refined Analysis
  82. Fermi GRB 240422A: Global MASTER-Net observations report
  83. GRB 240421B: AstroSat CZTI detection
  84. GRB 240422A: Fermi GBM Final Real-time Localization
  85. GRB240421B: Zadko Observations
  86. Fermi GRB 240421B: Global MASTER-Net observations report
  87. Swift GRB 240421B: Global MASTER-Net observations report
  88. GRB 240421B: Fermi GBM Observation
  89. GRB 240421B: Swift-XRT refined Analysis
  90. GRB240421B: BOOTES-5/JGT optical upper limit
  91. GRB 240421B: J-band upper limits from WINTER
  92. GRB 240421B: Swift/UVOT Upper Limits
  93. Fermi GRB 240421A: Global MASTER-Net observations report
  94. EP240417a: no counterpart detection by SOAR
  95. EP240420a: Xinglong decaying optical counterpart
  96. GRB 240421B: Swift detection of a burst
  97. EP240420a: Nanshan optical counterpart observations
  98. GRB 240421A: Fermi GBM Final Real-time Localization
  99. EP240420a: NOT optical counterpart candidate and potential host
  100. Fermi trigger No 735280430: Global MASTER-Net observations report

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