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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"

45998 results found.

  1. Fermi GRB 250307A: Global MASTER-Net observations report
  2. Konus-Wind detection of GRB 250306A
  3. GRB 250307A: Fermi GBM Final Real-time Localization
  4. GRB 250306A: Swift-BAT refined analysis
  5. GRB 250306A: NuSTAR detection of the prompt emission
  6. EP250304a: MeerKAT detection of a possible radio counterpart
  7. IceCube-241016A: MASTER flaring blazar 5BZU J073038.29-320820.2 with Zhirkov effect
  8. GRB 250305A: AstroSat CZTI detection
  9. EP250302a:Xinglong optical observations
  10. GRB 250306A: AstroSat CZTI detection
  11. Fermi trigger No 762963055: Global MASTER-Net observations report
  12. Fermi Gamma-ray Burst Monitor trigger 762963055/250306591 is not a GRB
  13. Swift GRB 250306A: Global MASTER-Net observations report
  14. LIGO/Virgo/KAGRA S250207bg: Update-5 NED Galaxies in the Localization Volume
  15. GRB 250306A: Swift detection of a burst
  16. LIGO/Virgo/KAGRA S250207bg: Updated Sky localization
  17. GRB250101A: Radio upper limits from VLA observations
  18. LIGO/Virgo/KAGRA S250306ej: Retraction of GW compact binary merger candidate
  19. GRB 250305A: SVOM/GRM observation of a burst
  20. The EP-WXT trigger 01709132323 is likely a flaring star
  21. EP250304A: Upper limits from Fermi-GBM Observations
  22. Fermi GRB 250305A: Global MASTER-Net observations report
  23. Fermi-LAT Gamma-ray Observations of IceCube-250302A
  24. GRB 250305A: Fermi GBM Final Real-time Localization
  25. EP250302a: Optical Observations at CrAO and SAO RAS
  26. GRB 250219A: SVOM/C-GFT optical upper limit at early phase
  27. EP 250304A: Optical counterpart detection by LCO
  28. EP250302A: 1.3m DFOT optical afterglow detection
  29. IceCube-250302A: Upper limits from a search for additional neutrino events in IceCube
  30. EP250304a: refined analysis of the EP-WXT and EP-FXT observations
  31. Konus-Wind detection of GRB 250222A
  32. EP250304a: REM NIR upper limits
  33. IPN triangulation of GRB 250222A
  34. EP250304a: Swift/UVOT detection of an optical counterpart with a rising light curve
  35. EP250302a: Mondy Continued Optical Observations
  36. EP250304a: VLT/X-shooter redshift z = 0.200
  37. EP250304a: Swift-XRT detection of a fading X-ray source
  38. EP250304a: TRT optical counterpart detection
  39. LIGO/Virgo/KAGRA S250304cb: Identification of a GW compact binary merger candidate
  40. EP250304a: Global MASTER-Net observations report
  41. EP250304a: Einstein Probe detection of an X-ray transient
  42. The EP-WXT trigger 01709132212 is not a real source
  43. EP250302a: SVOM/VT optical observation
  44. LIGO/Virgo/KAGRA S250223dk and Swift/BAT-GUANO ID 762004910: Swift/UVOT Upper Limits
  45. EP250302a: SAO RAS optical observations
  46. EP250302a : GIT optical follow-up
  47. EP250302a: VLT/X-shooter redshift confirmation
  48. EP250225a: the candidate optical counterpart is an AGN
  49. EP250302a: Kinder optical follow-up observations
  50. LIGO/Virgo/KAGRA S250302av: 2 counterpart neutrino candidate events from an IceCube neutrino search
  51. EP250302a: Swift/UVOT detection
  52. EP250302a: NUTTelA-TAO Early Measurments
  53. EP250302a: optical observation from the INAF Asiago Observatory
  54. EP250302a: REM NIR upper limits
  55. IceCube-241113A: MASTER flaring blazar 5BZB J1311+0853 with Zhirkov effect
  56. EP250302a: Mondy Observations and Optical Light Curve
  57. EP250302a: VLT/MUSE optical redshift z = 1.131
  58. INTEGRAL: end of scientific operations
  59. EP250302A: VLT near-infrared observations
  60. EP250302A: VLT/X-shooter tentative redshift
  61. EP250302a: OHP/T193 optical and spectroscopic observations
  62. EP250302a: Global MASTER-Net observations report
  63. EP250302a: Xinglong F60B optical observation
  64. EP250302a: Swift-XRT observations of a fading X-ray source
  65. EP250302a: Einstein Probe detection of an X-ray transient
  66. EP250302a: SVOM/C-GFT optical observations
  67. GRB 250226A: GRANDMA Optical Observations
  68. EP250302a: Montarrenti Observatory optical detection
  69. Fermi GRB 250302A: Global MASTER-Net observations report
  70. EP250302a: FTW optical and NIR detection
  71. EP250302a: Nanshan/HMT optical counterpart detection
  72. IceCube-250302A - IceCube observation of a high-energy neutrino candidate track-like event
  73. GRB 250302A: Fermi GBM Final Real-time Localization
  74. GRB 250228A: Fermi GBM Final Localization
  75. The EP-WXT trigger 01709132140 is likely a flaring star
  76. LIGO/Virgo/KAGRA S250206dm: early X-ray upper limits from Einstein Probe WXT and preliminary results of FXT observations
  77. GRB 250225B: VLT near-infrared afterglow confirmation
  78. EP250228a: Optical observations with Kinder and Swift/UVOT
  79. Konus-Wind detection of GRB 250226A
  80. GRB 250225B: EIRSAT-1 GMOD Detection
  81. GRB 250226A: KAO Optical Upper Limit
  82. GRB 250226A: AbAO AS-32 Optical Upper Limit
  83. EP250227a: Global MASTER-Net observations report
  84. EP250223A: Upper limits from Fermi-GBM Observations
  85. EP250227a: TRT optical upper limit
  86. GRB 250225B: VLT/HAWKI near-infrared observations
  87. EP250227a: Optical upper limits with Kinder observations
  88. EP250227a: NOT optical observations
  89. EP250227a: Einstein Probe detected of a fast X-ray transient
  90. EP250228a: updates on the EP observations
  91. GRB 250226A: Fermi GBM Observation
  92. EP250225a: EP-FXT follow-up observation
  93. EP250223a: J band upper limit by SYSU 80cm telescope
  94. EP250228a: Swift/XRT localisation
  95. EP250228a: Global MASTER-Net observations report
  96. EP250228a: Einstein Probe detection of an X-ray transient
  97. GRB 250226A / EP250226a: LCO detection of the afterglow
  98. LIGO/Virgo/KAGRA S250227e: Updated Sky localization
  99. LIGO/Virgo/KAGRA S250226dl: Updated Sky localization
  100. GRB 250225B: VLT/Xshooter imaging

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