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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').

21783 results found.

  1. Fermi GRB 240502B: Global MASTER-Net observations report
  2. GRB 240502C: Fermi GBM Final Localization
  3. Fermi GRB 240502A: Global MASTER-Net observations report
  4. GRB 240430A: GRBAlpha detection
  5. GRB 240502B: Fermi GBM Final Real-time Localization
  6. LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet Transient Candidates
  7. Integral GRB240502.23: Global MASTER-Net observations report
  8. GRB 240502A: Fermi GBM Final Real-time Localization
  9. Fermi GRB 240501A: Global MASTER-Net observations report
  10. Fermi trigger No 736197684: Global MASTER-Net observations report
  11. GRB 240426A: VZLUSAT-2 detection
  12. GRB 240425A: VZLUSAT-2 detection
  13. GRB240430A: Fermi GBM Final Localization
  14. GRB 240501A: Fermi GBM Final Real-time Localization
  15. GRB 240408B: VZLUSAT-2 detection
  16. GRB 240407A: VZLUSAT-2 detection
  17. GRB 240425A: GRBAlpha detection
  18. Fermi-LAT gamma-ray observations of IceCube-240424A
  19. GRB 240429A: Fermi GBM Final Real-time Localization
  20. LIGO/Virgo/KAGRA S240422ed: GECKO/KMTNet ToO observations
  21. LIGO/Virgo/KAGRA S240429an: Retraction of GW compact binary merger candidate
  22. Fermi GRB 240428A: Global MASTER-Net observations report
  23. GRB 240428A: Fermi GBM Final Real-time Localization
  24. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility contuinued observations of S240422ed and candidate analysis
  25. LIGO/Virgo/KAGRA S240422ed: 2.5m PRL Telescope follow-up of the Swift/XRT source S240422ed_X190
  26. LIGO/Virgo/KAGRA S240422ed: Upper limits from GECAM Observations
  27. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA and Kilonova-Catcher galaxy targeting observations
  28. GRB 240425A: Fermi GBM Final Real-time Localization
  29. Fermi trigger No 735697285: Global MASTER-Net observations report
  30. GRB 240419B: Swift-BAT refined analysis
  31. GRB 240421B: Swift-BAT refined analysis
  32. GRB 240422A: Glowbug gamma-ray detection
  33. LIGO/Virgo/KAGRA S240422ed: Himalayan Chandra Telescope follow-up of the Swift/XRT source S240422ed_X101
  34. LIGO/Virgo/KAGRA S240422ed: No significant counterpart candidates in HAWC observations
  35. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  36. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  37. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  38. LIGO/Virgo/KAGRA S240422ed: Early X-ray Upper Limits from EP-WXT for the LVK Sky Localization Region
  39. LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
  40. GRB 240421B: GRBAlpha detection
  41. IceCube Alert 240424.08: Global MASTER-Net observations report
  42. LIGO/Virgo/KAGRA S240422ed: Potential Candidates from Magellan galaxy-based search
  43. LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search
  44. GRB 240419A: Swift-BAT refined analysis
  45. GRB 240418A: Swift-BAT refined analysis
  46. LIGO/Virgo/KAGRA S240423br: Retraction of GW compact binary merger candidate
  47. LIGO/Virgo/KAGRA S240422ed: WINTER near-infrared J-band observations
  48. LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  49. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility observations and candidates
  50. LIGO/Virgo/KAGRA S240422ed: AstroSat CZTI non-detection and upper limits
  51. LIGO/Virgo/KAGRA S240422ed: Upper limits from Fermi-GBM Observations
  52. LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO
  53. LIGO/Virgo/KAGRA S240422ed: Coverage and upper limits from MAXI/GSC observations
  54. LIGO/Virgo/KAGRA S240422ed: Global MASTER-Net observations report
  55. Fermi trigger No 735470374: Global MASTER-Net observations report
  56. GRB 240421A: Glowbug gamma-ray detection
  57. GRB 240414A: radio detection with the VLA
  58. Fermi-LAT gamma-ray observations of IceCube-240419A
  59. GRB 240414A: LBT optical detection
  60. GRB 240419B : MITSuME Akeno optical upper limits
  61. GRB 240415A: Swift-XRT refined Analysis
  62. Fermi GRB 240422A: Global MASTER-Net observations report
  63. GRB 240421B: AstroSat CZTI detection
  64. GRB 240422A: Fermi GBM Final Real-time Localization
  65. GRB240421B: Zadko Observations
  66. Fermi GRB 240421B: Global MASTER-Net observations report
  67. Swift GRB 240421B: Global MASTER-Net observations report
  68. GRB 240421B: Fermi GBM Observation
  69. GRB 240421B: Swift-XRT refined Analysis
  70. GRB240421B: BOOTES-5/JGT optical upper limit
  71. GRB 240421B: J-band upper limits from WINTER
  72. GRB 240421B: Swift/UVOT Upper Limits
  73. Fermi GRB 240421A: Global MASTER-Net observations report
  74. EP240417a: no counterpart detection by SOAR
  75. EP240420a: Xinglong decaying optical counterpart
  76. GRB 240421B: Swift detection of a burst
  77. EP240420a: Nanshan optical counterpart observations
  78. GRB 240421A: Fermi GBM Final Real-time Localization
  79. EP240420a: NOT optical counterpart candidate and potential host
  80. Fermi trigger No 735280430: Global MASTER-Net observations report
  81. GRB240419A: Skynet Optical Afterglow Analysis
  82. GRB240418A - Candidate afterglow from NIRES
  83. IceCube Alert 240419.98: Global MASTER-Net observations report
  84. GRB 240419B: Swift/UVOT Upper Limits
  85. IceCube-240419A - IceCube observation of a high-energy neutrino candidate track-like event
  86. IceCube-240419A - IceCube observation of a high-energy neutrino candidate track-like event
  87. GRB 240419A: Swift/UVOT Upper Limits
  88. GRB 240419B: Swift-XRT refined Analysis
  89. GRB 240419B: optical afterglow from the NOT
  90. LIGO/Virgo/KAGRA S240420aw: Retraction of GW compact binary merger candidate
  91. Swift GRB 240419B: Global MASTER-Net observations report
  92. Swift GRB 240419A: Global MASTER-Net observations report
  93. GRB 240418A: Swift/UVOT Upper Limits
  94. GRB 240419A: REM NIR afterglow detection
  95. GRB 240419A: Swift-XRT refined Analysis
  96. GRB 240418A: Swift-XRT refined Analysis
  97. GRB 240419B: Swift detection of a burst
  98. GRB 240411B: Swift/UVOT Detection
  99. Fermi trigger No 735089036: Global MASTER-Net observations report
  100. EP240414a: GMG observation

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