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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"

46004 results found.

  1. EP250308a: FTW optical and NIR upper limits
  2. EP250308a: Einstein Probe detection of an X-ray transient
  3. EP250308a: NOT optical upper limit
  4. GRB 250309A: Fermi GBM Final Real-time Localization
  5. GRB 250306A: EIRSAT-1 GMOD detection
  6. The EP-WXT trigger 01709132387 is likely a flaring star
  7. Fermi GRB 250307A: Global MASTER-Net observations report
  8. Konus-Wind detection of GRB 250306A
  9. GRB 250307A: Fermi GBM Final Real-time Localization
  10. GRB 250306A: Swift-BAT refined analysis
  11. GRB 250306A: NuSTAR detection of the prompt emission
  12. EP250304a: MeerKAT detection of a possible radio counterpart
  13. IceCube-241016A: MASTER flaring blazar 5BZU J073038.29-320820.2 with Zhirkov effect
  14. GRB 250305A: AstroSat CZTI detection
  15. EP250302a:Xinglong optical observations
  16. GRB 250306A: AstroSat CZTI detection
  17. Fermi trigger No 762963055: Global MASTER-Net observations report
  18. Fermi Gamma-ray Burst Monitor trigger 762963055/250306591 is not a GRB
  19. Swift GRB 250306A: Global MASTER-Net observations report
  20. LIGO/Virgo/KAGRA S250207bg: Update-5 NED Galaxies in the Localization Volume
  21. GRB 250306A: Swift detection of a burst
  22. LIGO/Virgo/KAGRA S250207bg: Updated Sky localization
  23. GRB250101A: Radio upper limits from VLA observations
  24. LIGO/Virgo/KAGRA S250306ej: Retraction of GW compact binary merger candidate
  25. GRB 250305A: SVOM/GRM observation of a burst
  26. The EP-WXT trigger 01709132323 is likely a flaring star
  27. EP250304A: Upper limits from Fermi-GBM Observations
  28. Fermi GRB 250305A: Global MASTER-Net observations report
  29. Fermi-LAT Gamma-ray Observations of IceCube-250302A
  30. GRB 250305A: Fermi GBM Final Real-time Localization
  31. EP250302a: Optical Observations at CrAO and SAO RAS
  32. GRB 250219A: SVOM/C-GFT optical upper limit at early phase
  33. EP 250304A: Optical counterpart detection by LCO
  34. EP250302A: 1.3m DFOT optical afterglow detection
  35. IceCube-250302A: Upper limits from a search for additional neutrino events in IceCube
  36. EP250304a: refined analysis of the EP-WXT and EP-FXT observations
  37. Konus-Wind detection of GRB 250222A
  38. EP250304a: REM NIR upper limits
  39. IPN triangulation of GRB 250222A
  40. EP250304a: Swift/UVOT detection of an optical counterpart with a rising light curve
  41. EP250302a: Mondy Continued Optical Observations
  42. EP250304a: VLT/X-shooter redshift z = 0.200
  43. EP250304a: Swift-XRT detection of a fading X-ray source
  44. EP250304a: TRT optical counterpart detection
  45. LIGO/Virgo/KAGRA S250304cb: Identification of a GW compact binary merger candidate
  46. EP250304a: Global MASTER-Net observations report
  47. EP250304a: Einstein Probe detection of an X-ray transient
  48. The EP-WXT trigger 01709132212 is not a real source
  49. EP250302a: SVOM/VT optical observation
  50. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Swift/UVOT Upper Limits
  51. EP250302a: SAO RAS optical observations
  52. EP250302a : GIT optical follow-up
  53. EP250302a: VLT/X-shooter redshift confirmation
  54. EP250225a: the candidate optical counterpart is an AGN
  55. EP250302a: Kinder optical follow-up observations
  56. LIGO/Virgo/KAGRA S250302av: 2 counterpart neutrino candidate events from an IceCube neutrino search
  57. EP250302a: Swift/UVOT detection
  58. EP250302a: NUTTelA-TAO Early Measurments
  59. EP250302a: optical observation from the INAF Asiago Observatory
  60. EP250302a: REM NIR upper limits
  61. IceCube-241113A: MASTER flaring blazar 5BZB J1311+0853 with Zhirkov effect
  62. EP250302a: Mondy Observations and Optical Light Curve
  63. EP250302a: VLT/MUSE optical redshift z = 1.131
  64. INTEGRAL: end of scientific operations
  65. EP250302A: VLT near-infrared observations
  66. EP250302A: VLT/X-shooter tentative redshift
  67. EP250302a: OHP/T193 optical and spectroscopic observations
  68. EP250302a: Global MASTER-Net observations report
  69. EP250302a: Xinglong F60B optical observation
  70. EP250302a: Swift-XRT observations of a fading X-ray source
  71. EP250302a: Einstein Probe detection of an X-ray transient
  72. EP250302a: SVOM/C-GFT optical observations
  73. GRB 250226A: GRANDMA Optical Observations
  74. EP250302a: Montarrenti Observatory optical detection
  75. Fermi GRB 250302A: Global MASTER-Net observations report
  76. EP250302a: FTW optical and NIR detection
  77. EP250302a: Nanshan/HMT optical counterpart detection
  78. IceCube-250302A - IceCube observation of a high-energy neutrino candidate track-like event
  79. GRB 250302A: Fermi GBM Final Real-time Localization
  80. GRB 250228A: Fermi GBM Final Localization
  81. The EP-WXT trigger 01709132140 is likely a flaring star
  82. LIGO/Virgo/KAGRA S250206dm: early X-ray upper limits from Einstein Probe WXT and preliminary results of FXT observations
  83. GRB 250225B: VLT near-infrared afterglow confirmation
  84. EP250228a: Optical observations with Kinder and Swift/UVOT
  85. Konus-Wind detection of GRB 250226A
  86. GRB 250225B: EIRSAT-1 GMOD Detection
  87. GRB 250226A: KAO Optical Upper Limit
  88. GRB 250226A: AbAO AS-32 Optical Upper Limit
  89. EP250227a: Global MASTER-Net observations report
  90. EP250223A: Upper limits from Fermi-GBM Observations
  91. EP250227a: TRT optical upper limit
  92. GRB 250225B: VLT/HAWKI near-infrared observations
  93. EP250227a: Optical upper limits with Kinder observations
  94. EP250227a: NOT optical observations
  95. EP250227a: Einstein Probe detected of a fast X-ray transient
  96. EP250228a: updates on the EP observations
  97. GRB 250226A: Fermi GBM Observation
  98. EP250225a: EP-FXT follow-up observation
  99. EP250223a: J band upper limit by SYSU 80cm telescope
  100. EP250228a: Swift/XRT localisation

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