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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.

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

21945 results found.

  1. EP250215a: EP-WXT detection and FXT follow-up observation of an X-ray transient
  2. EP250207b: Xinglong optical upper limit
  3. EP250212a: Xinglong optical upper limit
  4. LIGO/Virgo/KAGRA S250206dm: DECam GW-MMADS candidates
  5. GRB 250205A: VIRT Optical Upper Limit
  6. GRB 250205A: Leavitt Observatory optical upper limit
  7. GRB 250210A: GRBAlpha detection
  8. EP250207B: Chandra localization of the X-ray counterpart
  9. EP250212a: Liverpool Telescope optical upper limits
  10. GRB250101A: Radio upper limits from GMRT observations
  11. EP trigger 10202399251 (possibly EP250212a): NOT J-band upper limit
  12. EP250207B: GTC z-band Observations
  13. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Follow-up of AT2025ber
  14. GRB 250205A: Calapai Observatory, Massa S. Giorgio (Messina), upper limit
  15. EP250207b: NOT optical counterpart candidate
  16. LIGO/Virgo/KAGRA S250206dm: GECKO Continued Observaiton with 7DT
  17. LIGO/Virgo/KAGRA S250206dm: AT 2025bbo observations with WFST
  18. GRB 250205A / EP250205A: radio detection with the VLA
  19. EP250207b: Tentative z-band brightening source
  20. LIGO/Virgo/KAGRA S250206dm: Kinder confirmation of a possible artefact in AT 2025bbo
  21. Konus-Wind detection of GRB 250207A
  22. Konus-Wind detection of GRB 250206A
  23. GRB 250210A: SVOM/GRM observation of a long burst
  24. EP250207b: Liverpool Telescope possible optical counterpart
  25. LIGO/Virgo/KAGRA S250211be: Identification of a GW compact binary merger candidate
  26. LIGO/Virgo/KAGRA S250211aa: Updated Sky localization and EM Bright Classification
  27. LIGO/Virgo/KAGRA S250211aa: Identification of a GW compact binary merger candidate
  28. GRB 250207A: Skynet optical afterglow observations
  29. GRB 241128A: VIRT Optical Upper Limit
  30. EP250207b: Gemini GMOS-N z-band observations
  31. EP250207b: a new X-ray transient detected by Einstein Probe
  32. LIGO/Virgo/KAGRA S250206dm: Global MASTER-Net observations report
  33. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of AT2025bbo and Galaxies in the Localization Volume
  34. LIGO/Virgo/KAGRA S250206dm: Observations from WINTER
  35. GRB 250204B: GRBAlpha detection
  36. GRB 250204A: GRBAlpha detection
  37. LIGO/Virgo/KAGRA S250206dm & FRB 20250206A: MASTER observations and possible mother galaxy
  38. LIGO/Virgo/KAGRA S250206dm: Optical observations of candidate AT 2025bbo with Kinder
  39. GRB 250207A: 1.3m DFOT Optical observations
  40. LIGO/Virgo/KAGRA S250206dm: WFST follow-up observations
  41. LIGO/Virgo/KAGRA S250206dm: FRB 20250206A BOOTES-5 and 2.2m CAHA optical upper limits
  42. GRB 250129A: GRANDMA Continued Afterglow Detection
  43. LIGO/Virgo/KAGRA S250206dm: GECKO Observation with 7DT and KMTNet
  44. GRB 250205A: 1.3m DFOT optical upper limit
  45. LIGO/Virgo/KAGRA S250206dm: NEWFIRM NIR Observations
  46. GRB 250206A: Fermi-LAT detection
  47. GRB 250207B: Swift-XRT observations
  48. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  49. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the DDOTI optical candidates
  50. LIGO/Virgo/KAGRA S250208ad: Identification of a GW compact binary merger candidate
  51. LIGO/Virgo/KAGRA S250206dm: MMT galaxy targeted observations
  52. EP trigger 01709131361 (possible EP250207a): NOT optical observations and flaring star
  53. GRB 250207A: Enhanced Swift-XRT position
  54. LIGO/Virgo/KAGRA S250206dm: GOTO counterpart search update - AT2025bar
  55. GRB 250129A: ABObservatory SLOAN r’ afterglow detection
  56. GRB 250207A: REM IR afterglow detection
  57. LIGO/Virgo/KAGRA S250206dm: ATLAS observations of the skymap
  58. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limits
  59. IGO/Virgo/KAGRA S250206dm: Virtual Telescope Project upper limit for the Neutrino IceCube Candidate
  60. GRB 250207A: REM optical afterglow detection
  61. LIGO/Virgo/KAGRA S250207bg: Identification of a GW compact binary merger candidate
  62. GRB 250207A: Swift/UVOT Detection
  63. LIGO/Virgo/KAGRA S250206dm: DDOTI Upper Limit for the Neutrino IceCube Candidate
  64. LIGO/Virgo/KAGRA S250206dm: GOTO observations of optical candidates AT 2025azn and AT 2025azm
  65. LIGO/Virgo/KAGRA S250206dm: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  66. LIGO/Virgo/KAGRA S250206dm: COLIBRÍ/DDRAGO Observations of the AT 2025azn Optical Candidate
  67. GRB 250129A: Continued AbAO and Mondy optical observations
  68. LIGO/Virgo/KAGRA S250206dm: SAGUARO Detection of Two Potential Optical Counterparts
  69. GRB 250207A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  70. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  71. GRB 250207A: Swift detection of a burst with optical counterpart
  72. LIGO/Virgo/KAGRA S250206dm: Updated Sky localization and EM Bright Classification
  73. LIGO/Virgo/KAGRA S250206dm: Identification of a GW compact binary merger candidate
  74. GRB 250205A: Fermi GBM Observation
  75. GRB 250205A: REM NIR upper limit
  76. GRB 250205A: Swift/UVOT Upper Limits
  77. EP250205a/GRB 250205A: Einstein Probe observation
  78. GRB 250127C: SVOM/GRM observation of a burst
  79. GRB 250204B: SVOM/GRM observation of a likely short burst
  80. GRB 250205A: COLIBRÍ/DDRAGO Optical Afterglow Detection
  81. GRB 250205A: Redshift from OSIRIS+/GTC z = 3.55
  82. GRB250205A: SVOM/VT optical afterglow detection
  83. GRB 250205A: OHP/T193 optical counterpart candidate
  84. LIGO/Virgo/KAGRA S250205ee: Identification of a GW compact binary merger candidate
  85. GRB 250205A: SVOM detection of a burst
  86. Konus-Wind detection of GRB 250201A
  87. IPN triangulation of GRB 250201A
  88. Konus-Wind detection of GRB 250202B
  89. LIGO/Virgo/KAGRA S250205bk: Identification of a GW compact binary merger candidate
  90. IPN triangulation of GRB 250202B
  91. GRB 250129A: LCO late afterglow detection
  92. GRB 250129A: AbAO AS-32 and Mondy AZT-33IK optical observations
  93. LIGO/Virgo/KAGRA S250204ax: Identification of a GW compact binary merger candidate
  94. GRB 250129A: COLIBRÍ/DDRAGO Afterglow Detection
  95. GRB 250202B: NuSTAR detection of the prompt emission
  96. GRB 250202C: GRBAlpha detection
  97. GRB 250202B: Fermi GBM Detection
  98. GRB 250129a: Liverpool Telescope optical follow-up
  99. GRB 240129A: further SAO RAS optical observations
  100. GRB 250129A: 7DT Detection and Medium-band SED of Afterglow

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