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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').

5454 results found.

  1. GRB 240502A: Fermi GBM Observation
  2. GRB 240415A 1.3m DFOT Optical upper limit
  3. Fermi-LAT gamma-ray observations of IceCube-240424A
  4. LIGO/Virgo/KAGRA S240422ed: A transient discovered from Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  5. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  6. EP240426b: EP-WXT detection of a new fast X-ray transient
  7. EP240426a: YAHPT optical upper limit
  8. XMM-Newton observation of EP240426a
  9. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  10. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  11. LIGO/Virgo/KAGRA S240422ed: Continued Imaging of Mag24a
  12. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  13. LXT240402A/GRB240402B: Chandra X-ray detection
  14. LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  15. Fermi-LAT gamma-ray observations of IceCube-240419A
  16. GRB 240415B: Swift-XRT observations
  17. GRB 240415A: Swift-XRT refined Analysis
  18. GRB 240421B: Fermi GBM Observation
  19. GRB 240421B: Swift-XRT refined Analysis
  20. EP240420a: Nanshan optical counterpart observations
  21. EP240420a: detection of fading X-ray emission with refined position by EP-FXT
  22. GRB240418A - Candidate afterglow from NIRES
  23. GRB 240419B: Swift-XRT refined Analysis
  24. GRB 240419A: Swift-XRT refined Analysis
  25. GRB 240418A: Swift-XRT refined Analysis
  26. EP 240416a: Xinglong and NOT decaying optical counterpart
  27. EP240416a: Kinder optical counterpart candidate
  28. GRB 240415A: Fermi GBM Observation
  29. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  30. GRB 240415A: Earliest optical followup with the Kinder observations
  31. EP240414a: EP-FXT follow-up observation
  32. GRB 240414A: Fermi GBM Observation
  33. LXT 240402A/GRB 240402B: Swift follow-up observations
  34. EP240413a: Upper limits from GECAM-B Observation
  35. EP 240414a: NOT optical counterpart confirmation
  36. GRB 240414A: Swift-XRT refined Analysis
  37. GRB 240414A: Skynet Optical Afterglow Observations
  38. EP240414a: Kinder optical counterpart candidate possibly associated with the galaxy SDSS J124601.99-094309.3
  39. EP240413a: possible detection of the X-ray emission with EP-FXT after 14 hours
  40. Fermi-LAT gamma-ray observations of IceCube-240412A
  41. GRB 240411B: Kinder observations with Lulin observatory
  42. GRB 240411B: Swift-XRT refined Analysis
  43. GRB 240411B: 1.3m DFOT Optical observations
  44. EP240408a: Upper limits from GECAM-B Observation
  45. Swift Trigger 1220736: detection of 4U 1543-62.
  46. Fermi-LAT gamma-ray observations of IceCube-240327B
  47. Fermi-LAT gamma-ray observations of IceCube-240327A
  48. LXT 240402A/GRB 240402B: rest-frame energetics from Konus-Wind observation
  49. GRB/FXT 240402B: Kinder optical counterpart candidate
  50. GRB 240403A: Fermi GBM Detection
  51. LXT 240402A: EP-FXT detection of the X-ray afterglow
  52. X-ray transient EP240331a: Kinder optical upper limits
  53. X-ray transient EP 240315a: Second epoch Chandra observations
  54. GRB 240318A: Fermi GBM Observation
  55. Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
  56. X-ray transient EP 240315a: Chandra observations
  57. GRB 240317B: Fermi GBM Observation
  58. X-ray transient EP240315a: Kinder follow-up observations for AT 2024eju with Lulin observatory
  59. Changes to the Fermi-GBM Triggering Thresholds
  60. Fermi-LAT gamma-ray observations of IceCube-240307A
  61. GRB 240306A: Fermi GBM observation
  62. Konus-Wind detection of GRB 231118A
  63. GRB 240305A: Fermi GBM observation
  64. Fermi-LAT gamma-ray observations of IceCube-240229A
  65. GRB 240305C: AstroSat CZTI detection of a short burst
  66. GRB 240303B: Fermi GBM Detection
  67. GRB 240225B: Swift-XRT afterglow detection
  68. GRB 240215A: Swift-XRT afterglow detection
  69. GRB 240225B: further SAO RAS optical observations
  70. Konus-Wind detection of GRB 240225B (long)
  71. GRB 240225B: SAO RAS optical observations
  72. GRB 240225B: NOT optical observations
  73. GRB 240225B: Swift-XRT observations
  74. Transient EPW20240219aa: Kp-band imaging observations with NIRES
  75. Swift BAT Sub-Threshold Detection of EPW20240219aa
  76. GRB 240222A: Swift-XRT refined Analysis
  77. GRB 240222A: Fermi GBM Observation
  78. GRB 240215B: Fermi GBM Observation
  79. GRB 240218A: LBT H-band detection
  80. Konus-Wind detection of GRB 240218A
  81. GRB 240218A: Swift-XRT refined Analysis
  82. GRB 240218A: Fermi GBM Detection
  83. GRB 240215A: Fermi GBM Observation
  84. Gamma-ray flaring activity from the blazar 1ES 1959+650 observed by the Fermi-LAT
  85. GRB 240209A: Fermi GBM observation
  86. GRB 240128A: Further Swift-XRT observations
  87. Fermi-LAT gamma-ray observations of IceCube-240204A
  88. GRB240204A: Swift/UVOT Upper Limits
  89. Konus-Wind detection of GRB 240205B (long / very soft)
  90. GRB 240205B: Fermi GBM Observation
  91. GRB 240204A: Fermi GBM Observation
  92. GRB 240129A: Fermi GBM Observation
  93. GRB 240128A: Swift-XRT observations
  94. GRB 240123B: Fermi GBM Observation
  95. Fermi-LAT gamma-ray observations of IceCube-240123A
  96. GRB 240123A: further SAO RAS optical observations
  97. GRB 240123A: SAO RAS optical observations
  98. GRB 240122A: Swift/UVOT Upper Limits
  99. GRB 240123A: Swift-XRT refined Analysis
  100. GRB 240122A: Swift-XRT afterglow detection

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