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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').

5468 results found.

  1. GRB 240516A: Swift-XRT refined Analysis
  2. GRB 240516A: Fermi GBM Observation
  3. GRB 240514B: Fermi GBM Detection
  4. GRB 240513A: Fermi GBM observation
  5. GRB 240513A: Swift-XRT observations
  6. LAT GRB240513.31: Global MASTER-Net observations report
  7. GRB 240513A: Fermi-LAT detection
  8. GRB 240511A: Fermi GBM Observation
  9. GRB 240511A: Swift-XRT refined Analysis
  10. LIGO/Virgo/KAGRA S240422ed: P200 observations of AT2024hit
  11. GRB 240504A: Fermi GBM Observation
  12. EP240506a: TRT optical upper limit
  13. EP240506a: Optical upper limit with Kinder observations
  14. GRB 240502A: 1.3m DFOT Optical upper limit
  15. GRB 240502A: Fermi GBM Observation
  16. GRB 240415A 1.3m DFOT Optical upper limit
  17. Fermi-LAT gamma-ray observations of IceCube-240424A
  18. LIGO/Virgo/KAGRA S240422ed: A transient discovered from Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  19. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  20. EP240426b: EP-WXT detection of a new fast X-ray transient
  21. EP240426a: YAHPT optical upper limit
  22. XMM-Newton observation of EP240426a
  23. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  24. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  25. LIGO/Virgo/KAGRA S240422ed: Continued Imaging of Mag24a
  26. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  27. LXT240402A/GRB240402B: Chandra X-ray detection
  28. LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  29. Fermi-LAT gamma-ray observations of IceCube-240419A
  30. GRB 240415B: Swift-XRT observations
  31. GRB 240415A: Swift-XRT refined Analysis
  32. GRB 240421B: Fermi GBM Observation
  33. GRB 240421B: Swift-XRT refined Analysis
  34. EP240420a: Nanshan optical counterpart observations
  35. EP240420a: detection of fading X-ray emission with refined position by EP-FXT
  36. GRB240418A - Candidate afterglow from NIRES
  37. GRB 240419B: Swift-XRT refined Analysis
  38. GRB 240419A: Swift-XRT refined Analysis
  39. GRB 240418A: Swift-XRT refined Analysis
  40. EP 240416a: Xinglong and NOT decaying optical counterpart
  41. EP240416a: Kinder optical counterpart candidate
  42. GRB 240415A: Fermi GBM Observation
  43. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  44. GRB 240415A: Earliest optical followup with the Kinder observations
  45. EP240414a: EP-FXT follow-up observation
  46. GRB 240414A: Fermi GBM Observation
  47. LXT 240402A/GRB 240402B: Swift follow-up observations
  48. EP240413a: Upper limits from GECAM-B Observation
  49. EP 240414a: NOT optical counterpart confirmation
  50. GRB 240414A: Swift-XRT refined Analysis
  51. GRB 240414A: Skynet Optical Afterglow Observations
  52. EP240414a: Kinder optical counterpart candidate possibly associated with the galaxy SDSS J124601.99-094309.3
  53. EP240413a: possible detection of the X-ray emission with EP-FXT after 14 hours
  54. Fermi-LAT gamma-ray observations of IceCube-240412A
  55. GRB 240411B: Kinder observations with Lulin observatory
  56. GRB 240411B: Swift-XRT refined Analysis
  57. GRB 240411B: 1.3m DFOT Optical observations
  58. EP240408a: Upper limits from GECAM-B Observation
  59. Swift Trigger 1220736: detection of 4U 1543-62.
  60. Fermi-LAT gamma-ray observations of IceCube-240327B
  61. Fermi-LAT gamma-ray observations of IceCube-240327A
  62. LXT 240402A/GRB 240402B: rest-frame energetics from Konus-Wind observation
  63. GRB/FXT 240402B: Kinder optical counterpart candidate
  64. GRB 240403A: Fermi GBM Detection
  65. LXT 240402A: EP-FXT detection of the X-ray afterglow
  66. X-ray transient EP240331a: Kinder optical upper limits
  67. X-ray transient EP 240315a: Second epoch Chandra observations
  68. GRB 240318A: Fermi GBM Observation
  69. Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
  70. X-ray transient EP 240315a: Chandra observations
  71. GRB 240317B: Fermi GBM Observation
  72. X-ray transient EP240315a: Kinder follow-up observations for AT 2024eju with Lulin observatory
  73. Changes to the Fermi-GBM Triggering Thresholds
  74. Fermi-LAT gamma-ray observations of IceCube-240307A
  75. GRB 240306A: Fermi GBM observation
  76. Konus-Wind detection of GRB 231118A
  77. GRB 240305A: Fermi GBM observation
  78. Fermi-LAT gamma-ray observations of IceCube-240229A
  79. GRB 240305C: AstroSat CZTI detection of a short burst
  80. GRB 240303B: Fermi GBM Detection
  81. GRB 240225B: Swift-XRT afterglow detection
  82. GRB 240215A: Swift-XRT afterglow detection
  83. GRB 240225B: further SAO RAS optical observations
  84. Konus-Wind detection of GRB 240225B (long)
  85. GRB 240225B: SAO RAS optical observations
  86. GRB 240225B: NOT optical observations
  87. GRB 240225B: Swift-XRT observations
  88. Transient EPW20240219aa: Kp-band imaging observations with NIRES
  89. Swift BAT Sub-Threshold Detection of EPW20240219aa
  90. GRB 240222A: Swift-XRT refined Analysis
  91. GRB 240222A: Fermi GBM Observation
  92. GRB 240215B: Fermi GBM Observation
  93. GRB 240218A: LBT H-band detection
  94. Konus-Wind detection of GRB 240218A
  95. GRB 240218A: Swift-XRT refined Analysis
  96. GRB 240218A: Fermi GBM Detection
  97. GRB 240215A: Fermi GBM Observation
  98. Gamma-ray flaring activity from the blazar 1ES 1959+650 observed by the Fermi-LAT
  99. GRB 240209A: Fermi GBM observation
  100. GRB 240128A: Further Swift-XRT observations

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