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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"

32568 results found.

  1. GRB 251124A: Fermi GBM Localization by automated pipeline
  2. LIGO/Virgo/KAGRA S251112cm: AT 2025adht Kinder follow-up observations
  3. EP251124a: Optical upper limit with Kinder observations
  4. EP251118A: 6 GHz VLA Detection
  5. Fermi GRB 251124a: Global MASTER-Net observations report
  6. LIGO/Virgo/KAGRA S251105aj: SVOM/VT optical observations and preliminary results on SVOM J2320.0-2901
  7. LIGO/Virgo/KAGRA S251105aj: EP-FXT follow-up observations and preliminary results on SVOM J2320.0-2901
  8. EP251124a: GROWTH-India Telescope optical upper limits
  9. GRB 251116C: Swift-XRT confirmation of fading
  10. GRB 251122A/EP251122a: FTW optical and NIR observations
  11. GRB 251122A/EP251122A: 1.3m DFOT optical detection
  12. GRB 251122A / EP251122a: Xinglong 2.16m optical observation
  13. EP251118A: 3.6m DOT optical afterglow detection
  14. GRB 251122A / EP251122a: EP-FXT counterpart detection
  15. EP251122a: refined analysis of the EP-WXT and EP-FXT observations
  16. GRB 251122A / EP251122a: WFST optical observations
  17. GRB 251122A/EP251122a: SVOM/VT optical observations with VHF data
  18. GRB 251122A/EP251122a: Additional, deeper LCO optical r band upper limit
  19. GRB 251122A / EP251122a: LCO optical upper limits
  20. EP251122a / GRB 251122A: optical counterpart candidate with Kinder observations
  21. EP251122a: Global MASTER-Net observations report
  22. GRB 251122A/EP251122a: SVOM/C-GFT upper limit
  23. GRB 251122A / EP251122a: SVOM detection of a long burst
  24. EP251118a: Continued Optical Detection with Kinder observations
  25. LIGO/Virgo/KAGRA S251105aj: SVOM/ECLAIRs detection of a high-energy transient SVOM J2320.0-2901 through targeted search
  26. LIGO/Virgo/KAGRA S251112cm: SOAR spectroscopy of three TROVE TNS candidates
  27. GRB 251121A: Swift/BAT-GUANO localization skymap of a short burst
  28. GRB 251121A: Glowbug gamma-ray detection of a likely short burst
  29. EP251118a: Xinglong-2.16m optical observation
  30. GRB 251115A: Fermi GBM Observation
  31. EP251118A: 1.3m DFOT optical afterglow detection
  32. GRB 251118A: Swift/UVOT Detection
  33. EP251118a / GRB 251118C: SAO RAS optical observations
  34. GRB 251118A: Glowbug gamma-ray detection
  35. GRB 251118A: Fermi GBM Observation
  36. GRB 251103A: SVOM/ECLAIRs and SVOM/GRM joint refined analysis
  37. EP251118a: Optical detection with Kinder observations
  38. GRB 251118A: GECAM-B detection
  39. LIGO/Virgo/KAGRA S251112cm: SVOM/VT optical observations and preliminary results
  40. EP251118a / GRB 251118C: SVOM/VT optical observation
  41. GRB 251118A: NuSTAR detection of bright prompt emission
  42. EP251118a / GRB 251118C: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at CTIO
  43. GRB 251116C: NOT optical observations
  44. GRB 251118C: Glowbug gamma-ray detection of the fast X-ray transient EP251118A
  45. GRB 251118C: Swift/BAT rates detection of a burst with a possible association with EP 251118A
  46. EP251118A / GRB 251118C : MASTER optical counterpart observations
  47. GRB 251118C: SVOM/GRM observation of a possible gamma-ray counterpart of EP251118a
  48. Konus-Wind detection of GRB 251118C (EP251118a)
  49. EP251118a: FTW optical and NIR observations
  50. GRB 251117A: Insight-HXMT/HE detection
  51. GRB 251119A: SVOM trigger sb25111901 is not a GRB
  52. EP251118a: VLT near-infrared observation
  53. GRB 251116D: SVOM/GRM observation of a long GRB
  54. EP251118a: GOTO optical afterglow detection
  55. EP251118a: NOT spectroscopic redshift of z = 1.216
  56. EP251118a: Global MASTER-Net observations report
  57. EP251118a: preliminary result of EP-FXT follow-up observation
  58. GRB 251118A: Fermi-LAT detection
  59. EP251118a: NOT candidate optical counterpart
  60. GRB 251118A: Swift ToO observations
  61. EP251118a: Einstein Probe detected of a fast X-ray transient
  62. Fermi GRB 251118B: Global MASTER-Net observations report
  63. LIGO/Virgo/KAGRA S251112cm: Upper limits from Glowbug gamma-ray observations
  64. GRB 251117A: FTW Observations of Swift candidate X-ray sources
  65. GRB 251116C: SVOM/ECLAIRs refined analysis
  66. GRB 251116B: SVOM/ECLAIRs refined analysis
  67. GRB 251117A: AstroSat CZTI detection
  68. GRB 251114B: Insight-HXMT/HE detection
  69. GRB 251114B: GECAM-B detection of a short burst
  70. GRB 251117A: Fermi GBM observation
  71. GRB 251013C: Koshka, SAO RAS, Mondy, and CrAO optical observations, possible SN detection
  72. LIGO/Virgo/KAGRA S251117dq: Updated Sky localization
  73. GRB 251116D: Insight-HXMT/HE detection
  74. GRB 251117A: Swift/BAT-GUANO localization skymap of a short burst
  75. GRB 251117A: SVOM/GRM observation of a short burst
  76. GRB 251117A: Tiled Swift observations
  77. GRB 251117A: Fermi-LAT detection
  78. LIGO/Virgo/KAGRA S251117dq: Identification of a GW compact binary merger candidate
  79. GRB 251116C: Swift/BAT arcminute localization of a burst
  80. LIGO/Virgo/KAGRA S251112cm: J-GEM follow-up observations
  81. LIGO/Virgo/KAGRA S251112cm: Classification of reported candidates with SOAR/Goodman
  82. GRB 251116B: SVOM/VT optical upper limit
  83. LIGO/Virgo/KAGRA S251112cm: WFST follow-up observations and preliminary results
  84. LIGO/Virgo/KAGRA S251116en: Updated Sky localization
  85. GRB 251116D: Glowbug gamma-ray detection
  86. EP251023a: Assy AZT-20 optical observations
  87. EP251023a: UAFO and AbAO optical observations
  88. LIGO/Virgo/KAGRA S251112cm: EP-FXT follow-up observations
  89. The EP-WXT trigger 01709247588: more evidence of flaring star from Mondy optical observations
  90. GRB 251116C: SVOM/VT optical upper limit
  91. GRB 251025B: further Mondy optical observations
  92. GRB 251111A: Mondy optical upper limit
  93. GRB 251116B: EP-FXT follow-up observation
  94. LIGO/Virgo/KAGRA S251116en: Identification of a GW compact binary merger candidate
  95. LIGO/Virgo/KAGRA S251112cm: Observations with the NSF-DOE Vera C. Rubin Observatory
  96. GRB 251116B: LCO optical upper limits
  97. GRB 251116C: LCO optical upper limits
  98. LIGO/Virgo/KAGRA S251112cm: GRANDMA observations of the skymap
  99. LIGO/Virgo/KAGRA S251112cm: AT2025adht follow-up at Maidanak observatory by GRANDMA
  100. GRB 251115A: Tiled Swift observations

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