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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"

45780 results found.

  1. GRB 250305A: SVOM/GRM observation of a burst
  2. The EP-WXT trigger 01709132323 is likely a flaring star
  3. EP250304A: Upper limits from Fermi-GBM Observations
  4. Fermi GRB 250305A: Global MASTER-Net observations report
  5. Fermi-LAT Gamma-ray Observations of IceCube-250302A
  6. GRB 250305A: Fermi GBM Final Real-time Localization
  7. EP250302a: Optical Observations at CrAO and SAO RAS
  8. GRB 250219A: SVOM/C-GFT optical upper limit at early phase
  9. EP 250304A: Optical counterpart detection by LCO
  10. EP250302A: 1.3m DFOT optical afterglow detection
  11. IceCube-250302A: Upper limits from a search for additional neutrino events in IceCube
  12. EP250304a: refined analysis of the EP-WXT and EP-FXT observations
  13. Konus-Wind detection of GRB 250222A
  14. EP250304a: REM NIR upper limits
  15. IPN triangulation of GRB 250222A
  16. EP250304a: Swift/UVOT detection of an optical counterpart with a rising light curve
  17. EP250302a: Mondy Continued Optical Observations
  18. EP250304a: VLT/X-shooter redshift z = 0.200
  19. EP250304a: Swift-XRT detection of a fading X-ray source
  20. EP250304a: TRT optical counterpart detection
  21. LIGO/Virgo/KAGRA S250304cb: Identification of a GW compact binary merger candidate
  22. EP250304a: Global MASTER-Net observations report
  23. EP250304a: Einstein Probe detection of an X-ray transient
  24. The EP-WXT trigger 01709132212 is not a real source
  25. EP250302a: SVOM/VT optical observation
  26. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Swift/UVOT Upper Limits
  27. EP250302a: SAO RAS optical observations
  28. EP250302a : GIT optical follow-up
  29. EP250302a: VLT/X-shooter redshift confirmation
  30. EP250225a: the candidate optical counterpart is an AGN
  31. EP250302a: Kinder optical follow-up observations
  32. LIGO/Virgo/KAGRA S250302av: 2 counterpart neutrino candidate events from an IceCube neutrino search
  33. EP250302a: Swift/UVOT detection
  34. EP250302a: NUTTelA-TAO Early Measurments
  35. EP250302a: optical observation from the INAF Asiago Observatory
  36. EP250302a: REM NIR upper limits
  37. IceCube-241113A: MASTER flaring blazar 5BZB J1311+0853 with Zhirkov effect
  38. EP250302a: Mondy Observations and Optical Light Curve
  39. EP250302a: VLT/MUSE optical redshift z = 1.131
  40. INTEGRAL: end of scientific operations
  41. EP250302A: VLT near-infrared observations
  42. EP250302A: VLT/X-shooter tentative redshift
  43. EP250302a: OHP/T193 optical and spectroscopic observations
  44. EP250302a: Global MASTER-Net observations report
  45. EP250302a: Xinglong F60B optical observation
  46. EP250302a: Swift-XRT observations of a fading X-ray source
  47. EP250302a: Einstein Probe detection of an X-ray transient
  48. EP250302a: SVOM/C-GFT optical observations
  49. GRB 250226A: GRANDMA Optical Observations
  50. EP250302a: Montarrenti Observatory optical detection
  51. Fermi GRB 250302A: Global MASTER-Net observations report
  52. EP250302a: FTW optical and NIR detection
  53. EP250302a: Nanshan/HMT optical counterpart detection
  54. IceCube-250302A - IceCube observation of a high-energy neutrino candidate track-like event
  55. GRB 250302A: Fermi GBM Final Real-time Localization
  56. GRB 250228A: Fermi GBM Final Localization
  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. GRB 250225B: VLT near-infrared afterglow confirmation
  60. EP250228a: Optical observations with Kinder and Swift/UVOT
  61. Konus-Wind detection of GRB 250226A
  62. GRB 250225B: EIRSAT-1 GMOD Detection
  63. GRB 250226A: KAO Optical Upper Limit
  64. GRB 250226A: AbAO AS-32 Optical Upper Limit
  65. EP250227a: Global MASTER-Net observations report
  66. EP250223A: Upper limits from Fermi-GBM Observations
  67. EP250227a: TRT optical upper limit
  68. GRB 250225B: VLT/HAWKI near-infrared observations
  69. EP250227a: Optical upper limits with Kinder observations
  70. EP250227a: NOT optical observations
  71. EP250227a: Einstein Probe detected of a fast X-ray transient
  72. EP250228a: updates on the EP observations
  73. GRB 250226A: Fermi GBM Observation
  74. EP250225a: EP-FXT follow-up observation
  75. EP250223a: J band upper limit by SYSU 80cm telescope
  76. EP250228a: Swift/XRT localisation
  77. EP250228a: Global MASTER-Net observations report
  78. EP250228a: Einstein Probe detection of an X-ray transient
  79. GRB 250226A / EP250226a: LCO detection of the afterglow
  80. LIGO/Virgo/KAGRA S250227e: Updated Sky localization
  81. LIGO/Virgo/KAGRA S250226dl: Updated Sky localization
  82. GRB 250225B: VLT/Xshooter imaging
  83. GRB 250205A / EP250205A: further radio observations with the VLA
  84. GRB 250226B: INTEGRAL SPI-ACS and PICsIT detection
  85. EP250226a/GRB 250226A: INTEGRAL SPI-ACS and PICsIT detection
  86. GRB 250225B: INTEGRAL SPI-ACS detection
  87. EP250225a: NOT optical candidate counterpart
  88. EP250226a/GRB 250226A:Xinglong optical follow-up observations
  89. EP250226a / GRB 250226A: SVOM/VT optical observations
  90. EP250226a/GRB 250226A: refined analysis of the EP-WXT and FXT observations
  91. EP250225a: TRT optical upper limits
  92. EP250226a/GRB 250226A: 1.6m Mephisto observations
  93. LIGO/Virgo/KAGRA S250206dm: Upper limits from SVOM/GRM Observations
  94. EP250226a/GRB 250226A: Kinder optical follow-up observations
  95. LIGO/Virgo/KAGRA S250223dk: Insight-HXMT/HE sub-threshold detection of a burst (HEB 250223501)
  96. LIGO/Virgo/KAGRA S250227y: Retraction of GW compact binary merger candidate
  97. LIGO/Virgo/KAGRA S250227e: Identification of a GW compact binary merger candidate
  98. Fermi GRB 250226B: Global MASTER-Net observations report
  99. LIGO/Virgo/KAGRA S250226dl: Identification of a GW compact binary merger candidate
  100. GRB 250226B: Fermi GBM Final Real-time Localization

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