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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').
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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.

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

45798 results found.

  1. LIGO/Virgo/KAGRA S250206dm: FRB 20250206A & "Time Machine" Effect.
  2. EP-WXT trigger 01709131361: correction to GCN 39214
  3. EP trigger 01709131361 (possible EP250207a): NOT optical observations and flaring star
  4. GRB 250207A: Enhanced Swift-XRT position
  5. CHIME/FRB source FRB 20250206A detected less than 1 minute after LIGO-Virgo-Kagra (LVK) S250206dm, however the probability of spatial coincidence is order 0.1%
  6. LIGO/Virgo/KAGRA S250206dm: GOTO counterpart search update - AT2025bar
  7. EP-WXT trigger 01709131361 / LIGO/Virgo/KAGRA S250206dm: FTW optical and NIR observations
  8. GRB 250129A: ABObservatory SLOAN r’ afterglow detection
  9. GRB 250207A: REM IR afterglow detection
  10. LIGO/Virgo/KAGRA S250206dm: ATLAS observations of the skymap
  11. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS survey of the skymap for optical transients
  12. GRB 250207A: FRAM-Auger optical detection
  13. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limits
  14. GRB 250207B: Tiled Swift observations
  15. LIGO/Virgo/KAGRA S250207bg: NED Galaxies in the Localization Volume
  16. Konus-Wind detection of GRB 250204B
  17. IGO/Virgo/KAGRA S250206dm: Virtual Telescope Project upper limit for the Neutrino IceCube Candidate
  18. IceCube-250207A - IceCube observation of a high-energy neutrino candidate track-like event
  19. GRB 250207A: REM optical afterglow detection
  20. LIGO/Virgo/KAGRA S250207bg: Identification of a GW compact binary merger candidate
  21. LIGO/Virgo/KAGRA S250206dm:GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  22. GRB 250207A: Swift/UVOT Detection
  23. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limit for the Neutrino IceCube Candidate
  24. LIGO/Virgo/KAGRA S250206dm: GOTO observations of optical candidates AT 2025azn and AT 2025azm
  25. LIGO/Virgo/KAGRA S250206dm: SOAR galaxy targeted observations
  26. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS observations of AT2025azm and AT2025azn
  27. LIGO/Virgo/KAGRA S250206dm: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  28. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the AT 2025azn Optical Candidate
  29. GRB 250129A: Continued AbAO and Mondy optical observations
  30. LIGO/Virgo/KAGRA S250206dm: SAGUARO Detection of Two Potential Optical Counterparts
  31. GRB 250207B: MAXI/GSC detection
  32. The EP-WXT trigger 01709131347 is likely a flaring star
  33. The EP-WXT trigger 01709131332 is likely a flaring star
  34. The EP-WXT trigger 01709131290 is likely a flaring star
  35. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  36. LIGO/Virgo/KAGRA S250206dm: Updated-6 NED Galaxies in the Localization Volume
  37. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  38. LIGO/Virgo/KAGRA S250206dm: Upper limits from Fermi-GBM Observations
  39. GRB 250207A: Swift detection of a burst with optical counterpart
  40. GRB 250207A: Fermi GBM Final Real-time Localization
  41. Fermi-LAT Gamma-ray Observations of IceCube-250203A
  42. LIGO/Virgo/KAGRA S250206dm: Coverage and upper limits from MAXI/GSC observations
  43. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  44. LIGO/Virgo/KAGRA S250206dm: Updated NED Galaxies in the Localization Volume
  45. LIGO/Virgo/KAGRA S250206dm: Two counterpart neutrino candidates from IceCube neutrino searches
  46. LIGO/Virgo/KAGRA S250206dm: Identification of a GW compact binary merger candidate
  47. LIGO/Virgo/KAGRA S250206dm: NED Galaxies in the Localization Volume
  48. GRB 250206A: BALROG localization (Fermi Trigger 760564296 / GRB 250206827)
  49. GRB 250206A: Fermi GBM Final Real-time Localization
  50. GRB 250205A: Fermi GBM Observation
  51. GRB 250205A: REM NIR upper limit
  52. EP250205a/GRB 250205A: FTW optical and NIR observations of the counterpart
  53. GRB 250205A: Swift/UVOT Upper Limits
  54. LIGO/Virgo/KAGRA S250205ee: Updated Sky localization and Source Classification
  55. EP250205a/GRB 250205A: correction to the source localization
  56. EP250205a/GRB 250205A: Einstein Probe observation
  57. GRB 250127C: SVOM/GRM observation of a burst
  58. GRB 250204B: SVOM/GRM observation of a likely short burst
  59. GRB 250205A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  60. GRB 250205A: Swift/XRT detection
  61. GRB 250205A: Redshift from OSIRIS+/GTC z = 3.55
  62. GRB250205A: SVOM/VT optical afterglow detection
  63. GRB 250205A: GOTO optical upper limits
  64. GRB 250205A: OHP/T193 optical counterpart candidate
  65. GRB 250205A: Liverpool Telescope optical counterpart candidate detection
  66. LIGO/Virgo/KAGRA S250205ee: Identification of a GW compact binary merger candidate
  67. GRB 250205A: SVOM detection of a burst
  68. LIGO/Virgo/KAGRA S250205bk: NED Galaxies in the Localization Volume
  69. Konus-Wind detection of GRB 250201A
  70. IPN triangulation of GRB 250201A
  71. LIGO/Virgo/KAGRA S250205bk: Updated Sky localization
  72. Konus-Wind detection of GRB 250202B
  73. LIGO/Virgo/KAGRA S250205bk: Identification of a GW compact binary merger candidate
  74. GRB 250129A: Swift-BAT refined analysis
  75. EP 250108A: Upper limits from Fermi-GBM Observations
  76. IPN triangulation of GRB 250204B (short/hard)
  77. IPN triangulation of GRB 250202B
  78. LIGO/Virgo/KAGRA S250204ax: Updated Sky localization
  79. GRB 250204B: AstroSat CZTI detection of a short burst
  80. GRB 250204B: Fermi GBM Final Localization
  81. GRB 250129A: LCO late afterglow detection
  82. GRB 250129A: AbAO AS-32 and Mondy AZT-33IK optical observations
  83. GRB 250204A: Fermi GBM Final Real-time Localization
  84. LIGO/Virgo/KAGRA S250204ax: Identification of a GW compact binary merger candidate
  85. GRB 250129A: COLIBRÍ/DDRAGO Afterglow Detection
  86. GRB 250202B: NuSTAR detection of the prompt emission
  87. GRB 250202C: GRBAlpha detection
  88. GRB 250202B: Fermi GBM Detection
  89. IceCube-250203A - IceCube observation of a high-energy neutrino candidate track-like event
  90. GRB 250129a: Liverpool Telescope optical follow-up
  91. GRB 240129A: further SAO RAS optical observations
  92. GRB 250129A: 7DT Detection and Medium-band SED of Afterglow
  93. LIGO/Virgo/KAGRA S250202cu: Updated Sky localization
  94. The EP-WXT trigger 01709131196 is likely a flaring star
  95. GRB 250202C: Fermi GBM Final Real-time Localization
  96. LIGO/Virgo/KAGRA S250202cu: Identification of a GW compact binary merger candidate
  97. GRB 250129A: SVOM/C-GFT optical observations
  98. The EP-WXT trigger 01709131153 is not a real source
  99. GRB 250202B: AstroSat CZTI detection of a bright long GRB
  100. LIGO/Virgo/KAGRA S250202ad: Retraction of GW compact binary merger candidate

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