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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"

23585 results found.

  1. EP trigger 01709131361 (possible EP250207a): NOT optical observations and flaring star
  2. GRB 250207A: Enhanced Swift-XRT position
  3. 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%
  4. EP-WXT trigger 01709131361 / LIGO/Virgo/KAGRA S250206dm: FTW optical and NIR observations
  5. GRB 250129A: ABObservatory SLOAN r’ afterglow detection
  6. GRB 250207A: REM IR afterglow detection
  7. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS survey of the skymap for optical transients
  8. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limits
  9. LIGO/Virgo/KAGRA S250207bg: NED Galaxies in the Localization Volume
  10. IGO/Virgo/KAGRA S250206dm: Virtual Telescope Project upper limit for the Neutrino IceCube Candidate
  11. GRB 250207A: REM optical afterglow detection
  12. LIGO/Virgo/KAGRA S250207bg: Identification of a GW compact binary merger candidate
  13. LIGO/Virgo/KAGRA S250206dm:GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  14. GRB 250207A: Swift/UVOT Detection
  15. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limit for the Neutrino IceCube Candidate
  16. LIGO/Virgo/KAGRA S250206dm: GOTO observations of optical candidates AT 2025azn and AT 2025azm
  17. LIGO/Virgo/KAGRA S250206dm: Pan-STARRS observations of AT2025azm and AT2025azn
  18. LIGO/Virgo/KAGRA S250206dm: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  19. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the AT 2025azn Optical Candidate
  20. GRB 250129A: Continued AbAO and Mondy optical observations
  21. LIGO/Virgo/KAGRA S250206dm: SAGUARO Detection of Two Potential Optical Counterparts
  22. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  23. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  24. LIGO/Virgo/KAGRA S250206dm: Upper limits from Fermi-GBM Observations
  25. GRB 250207A: Swift detection of a burst with optical counterpart
  26. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  27. LIGO/Virgo/KAGRA S250206dm: Two counterpart neutrino candidates from IceCube neutrino searches
  28. LIGO/Virgo/KAGRA S250206dm: Identification of a GW compact binary merger candidate
  29. LIGO/Virgo/KAGRA S250206dm: NED Galaxies in the Localization Volume
  30. GRB 250205A: Fermi GBM Observation
  31. GRB 250205A: REM NIR upper limit
  32. GRB 250205A: Swift/UVOT Upper Limits
  33. EP250205a/GRB 250205A: Einstein Probe observation
  34. GRB 250127C: SVOM/GRM observation of a burst
  35. GRB 250204B: SVOM/GRM observation of a likely short burst
  36. GRB 250205A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  37. GRB 250205A: Redshift from OSIRIS+/GTC z = 3.55
  38. GRB250205A: SVOM/VT optical afterglow detection
  39. GRB 250205A: GOTO optical upper limits
  40. GRB 250205A: OHP/T193 optical counterpart candidate
  41. LIGO/Virgo/KAGRA S250205ee: Identification of a GW compact binary merger candidate
  42. GRB 250205A: SVOM detection of a burst
  43. IPN triangulation of GRB 250201A
  44. LIGO/Virgo/KAGRA S250205bk: Identification of a GW compact binary merger candidate
  45. IPN triangulation of GRB 250204B (short/hard)
  46. IPN triangulation of GRB 250202B
  47. GRB 250129A: LCO late afterglow detection
  48. GRB 250129A: AbAO AS-32 and Mondy AZT-33IK optical observations
  49. LIGO/Virgo/KAGRA S250204ax: Identification of a GW compact binary merger candidate
  50. GRB 250129A: COLIBRÍ/DDRAGO Afterglow Detection
  51. GRB 250129a: Liverpool Telescope optical follow-up
  52. GRB 240129A: further SAO RAS optical observations
  53. GRB 250129A: 7DT Detection and Medium-band SED of Afterglow
  54. LIGO/Virgo/KAGRA S250202cu: Identification of a GW compact binary merger candidate
  55. GRB 250129A: SVOM/C-GFT optical observations
  56. Swift GRB250129A: MASTER 4 days observations report
  57. GRB 250129A: 1.3m DFOT Optical observations
  58. GRB 250129A: Liverpool Telescope observations suggest continued engine activity
  59. GRB 250129A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations
  60. GRB 250129A: SAO RAS optical observations
  61. GRB 250129A: COLIBRÍ Continuing Detection of the Afterglow
  62. GRB 250129A: COLIBRÍ Optical Observations
  63. GRB 250129A: iTelescope optical observation
  64. GRB 250129a: Liverpool Telescope optical follow-up
  65. GRB 250129A: TNG NIR afterglow detection
  66. GRB 250129A: AKO Optical Afterglow Detection
  67. GRB 250129A: GRANDMA/TAROT optical afterglow detection
  68. GRB 250128B: SAO RAS Zeiss-1000 and CrAO ZTSh optical upper limits
  69. GRB 250128B: VLA radio upper limit
  70. Ep250125A: 1.3m DFOT optical upper limit
  71. GRB 250129A: Skynet optical observations
  72. GRB 250128B: Gemini-North optical extended source detection
  73. The EP-WXT trigger 01709131085: KAIT confirmation of the stellar flare
  74. GRB 250128B: TNG optical upper limit
  75. GRB 250129A: Swift/UVOT Detection
  76. GRB 250128B: VLT/HAWKI near-infrared observations
  77. GRB 250127A: CrAO and Terskol optical upper limits
  78. GRB 250129A: Enhanced Swift-XRT position
  79. GRB 250128B: NOT optical upper limit
  80. GRB 250128B: VLT/FORS2 optical observations
  81. GRB 250129A: REM optical/NIR afterglow detection
  82. GRB 250129A: OHP/T193 optical and spectroscopy observations
  83. GRB 250129A: Early afterglow detection by LCO.
  84. GRB 250128B: OHP/T193 optical upper limit
  85. GRB 250129A: LCO optical observations
  86. GRB 250128B: Enhanced Swift-XRT position
  87. GRB 250129A: Swift detection of a burst with an optical counterpart
  88. GRB 250128B: Swift-XRT refined Analysis
  89. GRB 250128B: GOTO optical upper limit
  90. Swift GRB 250128B: Global MASTER-Net observations report
  91. GRB 250128B: LCO optical observations
  92. GRB 250128B: Swift detection of a short burst
  93. GRB 250127A: Swift-XRT observations
  94. GRB 250127B: DDOTI Upper Limit on the Afterglow
  95. Fermi GRB 250128A: Global MASTER-Net observations report
  96. GRB 250127A: SVOM/VT upper limit
  97. IPN triangulation of GRB 250119C
  98. GRB 250127A: LCO optical upper limit
  99. GRB 241223A: cubesat Avion detection
  100. EP250125a: Optical upper limit with Kinder observations

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