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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').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

6788 results found.

  1. Swift Trigger 1235109: a possible GRB 240606A
  2. Swift Trigger 1232755: likely consistent with noise and not astrophysical
  3. Swift Trigger 1232465: consistent with noise
  4. GRB 240529A: continued SAO RAS optical observations
  5. GRB 240529A: OSN optical detection
  6. The EP-WXT source triggered on June 1st is likely a flaring star
  7. GRB 240529A: further SAO RAS optical observations
  8. GRB 240529A: 1.3m DFOT Optical observations
  9. Konus-Wind detection of GRB 240529A
  10. IPN triangulation of the initial episode of GRB 240529A
  11. GRB 240529A: SAO RAS optical observations
  12. GRB 240529A: optical photometry from Konkoly
  13. GRB 240529A: Swift-XRT refined Analysis
  14. GRB 240527B: Swift-XRT afterglow detection
  15. GRB 240527B: Fermi GBM Observation
  16. GRB 240527B: Fermi-LAT detection
  17. GRB 240523A: Swift-XRT refined Analysis
  18. GRB 240521B: Fermi GBM Observation
  19. Fermi GBM Sub-Threshold Detection of GRB 240516B
  20. EP240518a: possibly identified with a flare star by EP-FXT
  21. GRB 240516A: Swift-XRT refined Analysis
  22. GRB 240516A: Fermi GBM Observation
  23. GRB 240514B: Fermi GBM Detection
  24. GRB 240513A: Fermi GBM observation
  25. GRB 240513A: Swift-XRT observations
  26. LAT GRB240513.31: Global MASTER-Net observations report
  27. GRB 240513A: Fermi-LAT detection
  28. GRB 240511A: Fermi GBM Observation
  29. GRB 240511A: Swift-XRT refined Analysis
  30. LIGO/Virgo/KAGRA S240422ed: P200 observations of AT2024hit
  31. GRB 240504A: Fermi GBM Observation
  32. EP240506a: TRT optical upper limit
  33. EP240506a: Optical upper limit with Kinder observations
  34. GRB 240502A: 1.3m DFOT Optical upper limit
  35. GRB 240502A: Fermi GBM Observation
  36. GRB 240415A 1.3m DFOT Optical upper limit
  37. Fermi-LAT gamma-ray observations of IceCube-240424A
  38. LIGO/Virgo/KAGRA S240422ed: A transient discovered from Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  39. LIGO/Virgo S240422ed: Swift XRT observation of EP240426a
  40. EP240426b: EP-WXT detection of a new fast X-ray transient
  41. EP240426a: YAHPT optical upper limit
  42. XMM-Newton observation of EP240426a
  43. LIGO/Virgo/KAGRA S240422ed: Further near-infrared observations with Subaru/MOIRCS by J-GEM Collaboration
  44. LIGO/Virgo S240422ed: Swift-XRT detection of 3 possible counterparts
  45. LIGO/Virgo/KAGRA S240422ed: Continued Imaging of Mag24a
  46. LIGO/Virgo/KAGRA S240422ed: Subaru/MOIRCS near-infrared observations by J-GEM Collaboration
  47. LXT240402A/GRB240402B: Chandra X-ray detection
  48. LIGO/Virgo S240422ed: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  49. Fermi-LAT gamma-ray observations of IceCube-240419A
  50. GRB 240415B: Swift-XRT observations
  51. GRB 240415A: Swift-XRT refined Analysis
  52. GRB 240421B: Fermi GBM Observation
  53. GRB 240421B: Swift-XRT refined Analysis
  54. EP240420a: Nanshan optical counterpart observations
  55. EP240420a: detection of fading X-ray emission with refined position by EP-FXT
  56. GRB240418A - Candidate afterglow from NIRES
  57. GRB 240419B: Swift-XRT refined Analysis
  58. GRB 240419A: Swift-XRT refined Analysis
  59. GRB 240418A: Swift-XRT refined Analysis
  60. EP 240416a: Xinglong and NOT decaying optical counterpart
  61. EP240416a: Kinder optical counterpart candidate
  62. GRB 240415A: Fermi GBM Observation
  63. GRB 240414A: GAD Observatory, La Spezia, Italy ,upper limit
  64. GRB 240415A: Earliest optical followup with the Kinder observations
  65. EP240414a: EP-FXT follow-up observation
  66. GRB 240414A: Fermi GBM Observation
  67. LXT 240402A/GRB 240402B: Swift follow-up observations
  68. EP240413a: Upper limits from GECAM-B Observation
  69. EP 240414a: NOT optical counterpart confirmation
  70. GRB 240414A: Swift-XRT refined Analysis
  71. GRB 240414A: Skynet Optical Afterglow Observations
  72. EP240414a: Kinder optical counterpart candidate possibly associated with the galaxy SDSS J124601.99-094309.3
  73. EP240413a: possible detection of the X-ray emission with EP-FXT after 14 hours
  74. Fermi-LAT gamma-ray observations of IceCube-240412A
  75. GRB 240411B: Kinder observations with Lulin observatory
  76. GRB 240411B: Swift-XRT refined Analysis
  77. GRB 240411B: 1.3m DFOT Optical observations
  78. EP240408a: Upper limits from GECAM-B Observation
  79. Swift Trigger 1220736: detection of 4U 1543-62.
  80. Fermi-LAT gamma-ray observations of IceCube-240327B
  81. Fermi-LAT gamma-ray observations of IceCube-240327A
  82. LXT 240402A/GRB 240402B: rest-frame energetics from Konus-Wind observation
  83. GRB/FXT 240402B: Kinder optical counterpart candidate
  84. GRB 240403A: Fermi GBM Detection
  85. LXT 240402A: EP-FXT detection of the X-ray afterglow
  86. X-ray transient EP240331a: Kinder optical upper limits
  87. X-ray transient EP 240315a: Second epoch Chandra observations
  88. GRB 240318A: Fermi GBM Observation
  89. Konus-Wind detection of GRB 240315C (possible counterpart of EP240315a)
  90. X-ray transient EP 240315a: Chandra observations
  91. GRB 240317B: Fermi GBM Observation
  92. X-ray transient EP240315a: Kinder follow-up observations for AT 2024eju with Lulin observatory
  93. Changes to the Fermi-GBM Triggering Thresholds
  94. Fermi-LAT gamma-ray observations of IceCube-240307A
  95. GRB 240306A: Fermi GBM observation
  96. Konus-Wind detection of GRB 231118A
  97. GRB 240305A: Fermi GBM observation
  98. Fermi-LAT gamma-ray observations of IceCube-240229A
  99. GRB 240305C: AstroSat CZTI detection of a short burst
  100. GRB 240303B: Fermi GBM Detection

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