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GCN Circulars

GCN Circulars are rapid bulletins submitted by and distributed to the community. 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"

3379 results found.

  1. The EP-WXT trigger 01709132801 is likely a flaring star
  2. GRB 250315A/EP250315A: Fermi-GBM Sub-Threshold Detection
  3. GRB 250314A: EP-FXT afterglow detection
  4. EP250315a: refined analysis of the EP-WXT and EP-FXT observations
  5. EP250315a: optical counterpart candidate detected by Gemini North
  6. EP250315a: Einstein Probe detection of an X-ray transient
  7. Konus-Wind detection of GRB 250313A
  8. Konus-Wind detection of GRB 250308A
  9. EP250311a/GRB 250311A: Correction to EP-WXT detection time
  10. EP250304a: Pan-STARRS r and i-band imaging and photometry
  11. EP trigger ID 01709061302: Lick/Kast spectroscopy with the 3 m Shane telescope
  12. The EP-WXT trigger 01709132551 is not a real source
  13. EP250311a/GRB 250311A: EP-FXT follow-up observation
  14. EP250302a: Chandra X-ray Detection
  15. GRB 250311A/EP250311a: Optical upper limits with Kinder observations
  16. EP250311a: Global MASTER-Net observations report
  17. GRB 250226A: Swift/BAT-GUANO localization skymap of a long GRB
  18. EP250304a: Chandra detection
  19. GRB 250311A/EP250311a: TRT optical upper limit
  20. EP250311a/GRB 250311A: EP-WXT detection
  21. The EP-WXT trigger 01709132425 is not a real source
  22. Konus-Wind detection of GRB 250309B
  23. EP250308a: Global MASTER-Net observations report
  24. EP250308a: GSP optical upper limit
  25. EP250308a: FTW optical and NIR upper limits
  26. EP250308a: Einstein Probe detection of an X-ray transient
  27. EP250308a: NOT optical upper limit
  28. The EP-WXT trigger 01709132387 is likely a flaring star
  29. Konus-Wind detection of GRB 250306A
  30. EP250304a: MeerKAT detection of a possible radio counterpart
  31. EP250302a:Xinglong optical observations
  32. The EP-WXT trigger 01709132323 is likely a flaring star
  33. EP250304A: Upper limits from Fermi-GBM Observations
  34. EP 250304A: Optical counterpart detection by LCO
  35. EP250302A: 1.3m DFOT optical afterglow detection
  36. EP250304a: refined analysis of the EP-WXT and EP-FXT observations
  37. Konus-Wind detection of GRB 250222A
  38. EP250304a: Swift/UVOT detection of an optical counterpart with a rising light curve
  39. EP250304a: Swift-XRT detection of a fading X-ray source
  40. EP250304a: TRT optical counterpart detection
  41. EP250304a: Global MASTER-Net observations report
  42. EP250304a: Einstein Probe detection of an X-ray transient
  43. The EP-WXT trigger 01709132212 is not a real source
  44. EP250302a : GIT optical follow-up
  45. EP250302a: VLT/X-shooter redshift confirmation
  46. EP250302a: Kinder optical follow-up observations
  47. EP250302a: Swift/UVOT detection
  48. EP250302a: NUTTelA-TAO Early Measurments
  49. EP250302A: VLT/X-shooter tentative redshift
  50. EP250302a: Global MASTER-Net observations report
  51. EP250302a: Xinglong F60B optical observation
  52. EP250302a: Einstein Probe detection of an X-ray transient
  53. GRB 250226A: GRANDMA Optical Observations
  54. EP250302a: Montarrenti Observatory optical detection
  55. EP250302a: FTW optical and NIR detection
  56. EP250302a: Nanshan/HMT optical counterpart detection
  57. The EP-WXT trigger 01709132140 is likely a flaring star
  58. LIGO/Virgo/KAGRA S250206dm: early X-ray upper limits from Einstein Probe WXT and preliminary results of FXT observations
  59. EP250228a: Optical observations with Kinder and Swift/UVOT
  60. Konus-Wind detection of GRB 250226A
  61. EP250227a: Global MASTER-Net observations report
  62. EP250223A: Upper limits from Fermi-GBM Observations
  63. EP250227a: TRT optical upper limit
  64. EP250227a: Optical upper limits with Kinder observations
  65. EP250227a: NOT optical observations
  66. EP250227a: Einstein Probe detected of a fast X-ray transient
  67. EP250228a: updates on the EP observations
  68. GRB 250226A: Fermi GBM Observation
  69. EP250225a: EP-FXT follow-up observation
  70. EP250223a: J band upper limit by SYSU 80cm telescope
  71. EP250228a: Swift/XRT localisation
  72. EP250228a: Global MASTER-Net observations report
  73. EP250228a: Einstein Probe detection of an X-ray transient
  74. GRB 250226A / EP250226a: LCO detection of the afterglow
  75. EP250226a/GRB 250226A: INTEGRAL SPI-ACS and PICsIT detection
  76. EP250225a: NOT optical candidate counterpart
  77. EP250226a/GRB 250226A: refined analysis of the EP-WXT and FXT observations
  78. EP250225a: TRT optical upper limits
  79. EP250226a/GRB 250226A: Kinder optical follow-up observations
  80. Konus-Wind detection of GRB 250225B
  81. GRB 250226A: GECAM-B detection
  82. GRB 250221A: EP-FXT detection of the X-ray afterglow
  83. EP250226a/GRB 250226A: GSP detects optical counterpart
  84. EP250226a / GRB 250226A: TRT optical counterpart observation
  85. EP250226a: Global MASTER-Net observations report
  86. EP250226a/GRB 250226A: EP-WXT detection and FXT follow-up observation of an X-ray transient
  87. EP250225a: Global MASTER-Net observations report
  88. EP250225a: GSP optical upper limit
  89. EP250223a: GMG Optical Observation
  90. EP250225a: Einstein Probe detected of a fast X-ray transient
  91. EP250223a: GROWTH-India Telescope optical observations
  92. EP250215A: J band upper limit by SYSU 80cm telescope
  93. EP250223a: Kinder optical follow-up observations
  94. GRB 250219A: EP-FXT afterglow detection
  95. EP250223a: GOTO optical afterglow detections
  96. EP250223a: TRT optical afterglow observation
  97. EP250223a: refined analysis of the EP-WXT and FXT observations
  98. EP250223a: 1.6m Mephisto and 50cm array observations
  99. EP250223a: SVOM/VT optical observation
  100. The EP-WXT trigger 01709131882 is likely a flaring star

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