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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').

21174 results found.

  1. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility contuinued observations of S240422ed and candidate analysis
  2. LIGO/Virgo/KAGRA S240422ed: 2.5m PRL Telescope follow-up of the Swift/XRT source S240422ed_X190
  3. LIGO/Virgo/KAGRA S240422ed: Upper limits from GECAM Observations
  4. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA and Kilonova-Catcher galaxy targeting observations
  5. GRB 240425A: Fermi GBM Final Real-time Localization
  6. Fermi trigger No 735697285: Global MASTER-Net observations report
  7. GRB 240419B: Swift-BAT refined analysis
  8. GRB 240421B: Swift-BAT refined analysis
  9. LIGO/Virgo/KAGRA S240422ed: Himalayan Chandra Telescope follow-up of the Swift/XRT source S240422ed_X101
  10. LIGO/Virgo/KAGRA S240422ed: No significant counterpart candidates in HAWC observations
  11. LIGO/Virgo/KAGRA S240422ed: No significant candidates in GRANDMA/FRAM Observations
  12. IceCube-240424A - IceCube observation of a high-energy neutrino candidate track-like event
  13. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  14. LIGO/Virgo/KAGRA S240422ed: Early X-ray Upper Limits from EP-WXT for the LVK Sky Localization Region
  15. LIGO/Virgo/KAGRA S240422ed: NOT J-band upper limit on the Swift/XRT source S240422ed_X61
  16. GRB 240421B: GRBAlpha detection
  17. IceCube Alert 240424.08: Global MASTER-Net observations report
  18. LIGO/Virgo/KAGRA S240422ed: Potential Candidates from Magellan galaxy-based search
  19. LIGO/Virgo/KAGRA S240422ed: GOTO counterpart search
  20. GRB 240419A: Swift-BAT refined analysis
  21. GRB 240418A: Swift-BAT refined analysis
  22. LIGO/Virgo/KAGRA S240423br: Retraction of GW compact binary merger candidate
  23. LIGO/Virgo/KAGRA S240422ed: WINTER near-infrared J-band observations
  24. LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  25. LIGO/Virgo/KAGRA S240422ed: Zwicky Transient Facility observations and candidates
  26. LIGO/Virgo/KAGRA S240422ed: AstroSat CZTI non-detection and upper limits
  27. LIGO/Virgo/KAGRA S240422ed: Upper limits from Fermi-GBM Observations
  28. LIGO/Virgo/KAGRA S240421ar: Upper limits from Swift/BAT-GUANO
  29. LIGO/Virgo/KAGRA S240422ed: Coverage and upper limits from MAXI/GSC observations
  30. LIGO/Virgo/KAGRA S240422ed: Global MASTER-Net observations report
  31. Fermi trigger No 735470374: Global MASTER-Net observations report
  32. GRB 240414A: LBT optical detection
  33. GRB 240419B : MITSuME Akeno optical upper limits
  34. GRB 240415B: Swift-XRT observations
  35. GRB 240415A: Swift-XRT refined Analysis
  36. Fermi GRB 240422A: Global MASTER-Net observations report
  37. GRB 240421B: AstroSat CZTI detection
  38. GRB 240422A: Fermi GBM Final Real-time Localization
  39. GRB240421B: Zadko Observations
  40. Fermi GRB 240421B: Global MASTER-Net observations report
  41. Swift GRB 240421B: Global MASTER-Net observations report
  42. GRB 240421B: Fermi GBM Observation
  43. GRB 240421B: Swift-XRT refined Analysis
  44. GRB240421B: BOOTES-5/JGT optical upper limit
  45. GRB 240421B: J-band upper limits from WINTER
  46. GRB 240421B: Swift/UVOT Upper Limits
  47. Fermi GRB 240421A: Global MASTER-Net observations report
  48. EP240417a: no counterpart detection by SOAR
  49. EP240420a: Xinglong decaying optical counterpart
  50. GRB 240421B: Swift detection of a burst
  51. EP240420a: Nanshan optical counterpart observations
  52. GRB 240421A: Fermi GBM Final Real-time Localization
  53. EP240420a: NOT optical counterpart candidate and potential host
  54. Fermi trigger No 735280430: Global MASTER-Net observations report
  55. GRB240419A: Skynet Optical Afterglow Analysis
  56. GRB240418A - Candidate afterglow from NIRES
  57. IceCube Alert 240419.98: Global MASTER-Net observations report
  58. GRB 240419B: Swift/UVOT Upper Limits
  59. GRB 240419A: Swift/UVOT Upper Limits
  60. GRB 240419B: Swift-XRT refined Analysis
  61. GRB 240419B: optical afterglow from the NOT
  62. LIGO/Virgo/KAGRA S240420aw: Retraction of GW compact binary merger candidate
  63. Swift GRB 240419B: Global MASTER-Net observations report
  64. Swift GRB 240419A: Global MASTER-Net observations report
  65. GRB 240418A: Swift/UVOT Upper Limits
  66. GRB 240419A: REM NIR afterglow detection
  67. GRB 240419A: Swift-XRT refined Analysis
  68. GRB 240418A: Swift-XRT refined Analysis
  69. GRB 240419B: Swift detection of a burst
  70. GRB 240411B: Swift/UVOT Detection
  71. Fermi trigger No 735089036: Global MASTER-Net observations report
  72. EP240414a: GMG observation
  73. GRB 240419A: Swift detection of a burst
  74. GRB 240418A: NOT optical upper limits
  75. GRB 240418A: AKO Upper Limit
  76. GRB 240411A: GOTO early optical upper limits
  77. Swift GRB240418.85: Global MASTER-Net observations report
  78. GRB 240418A: Swift detection of a burst
  79. Fermi GRB 240417A: Global MASTER-Net observations report
  80. Improved IPN triangulation of GRB 240411A
  81. GRB 240417A: Fermi GBM Final Real-time Localization
  82. GRB 240415A: Glowbug gamma-ray detection
  83. GRB 240414A: Glowbug gamma-ray detection
  84. GRB 240415B: GECAM-B detection
  85. EP 240416a: Xinglong and NOT decaying optical counterpart
  86. GRB 240415A: Swift-BAT refined analysis
  87. EP240416A: MASTER optical observations
  88. GRB 240411A: Glowbug gamma-ray detection
  89. GRB 240414A: Swift-BAT refined analysis
  90. EP240416a: Kinder optical counterpart candidate
  91. GRB 240414A: AbAO optical upprer limit
  92. GRB 240415A: Swift/UVOT Detection
  93. GRB 240415A: Fermi GBM Observation
  94. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  95. GRB 240414A: GMG observation
  96. GRB 240415B: Swift ToO observations
  97. GRB 240415B: Swift/BAT-GUANO Correction
  98. GRB 240415B: Swift/BAT-GUANO arcminute localization of a short burst
  99. GRB 240415A: OHP/T193 optical observations
  100. GRB 240414A: Fermi GBM Observation

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