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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"

32578 results found.

  1. EP251124b follow-up observation by EP-FXT
  2. GRB 251125B: COLIBRÍ observations of fading of the MASTER OT candidate
  3. EP251124b: NOT r- and z-band optical upper limits
  4. Fermi GRB 251125B : MASTER OT J155558.56+581224.1 optical counterpart discovery
  5. Fermi GRB 251125B: Global MASTER-Net observations report
  6. EP251124b: Global MASTER-Net observations report
  7. EP251124a: Xinglong GWAC-F60A optical observation
  8. EP251124a (EP-WXT trigger 01709248862) is triggered by the known source AWM 7
  9. Fermi GRB 251125A: Global MASTER-Net observations report
  10. EP251124a: NOT r- and z-band optical upper limits
  11. EP251124a: Global MASTER-Net observations report
  12. GRB 251124A: Fermi GBM Localization by automated pipeline
  13. LIGO/Virgo/KAGRA S251112cm: AT 2025adht Kinder follow-up observations
  14. EP251124a: Optical upper limit with Kinder observations
  15. EP251118A: 6 GHz VLA Detection
  16. Fermi GRB 251124a: Global MASTER-Net observations report
  17. LIGO/Virgo/KAGRA S251105aj: SVOM/VT optical observations and preliminary results on SVOM J2320.0-2901
  18. LIGO/Virgo/KAGRA S251105aj: EP-FXT follow-up observations and preliminary results on SVOM J2320.0-2901
  19. EP251124a: GROWTH-India Telescope optical upper limits
  20. GRB 251116C: Swift-XRT confirmation of fading
  21. GRB 251122A/EP251122a: FTW optical and NIR observations
  22. GRB 251122A/EP251122A: 1.3m DFOT optical detection
  23. GRB 251122A / EP251122a: Xinglong 2.16m optical observation
  24. EP251118A: 3.6m DOT optical afterglow detection
  25. GRB 251122A / EP251122a: EP-FXT counterpart detection
  26. EP251122a: refined analysis of the EP-WXT and EP-FXT observations
  27. GRB 251122A / EP251122a: WFST optical observations
  28. GRB 251122A/EP251122a: SVOM/VT optical observations with VHF data
  29. GRB 251122A/EP251122a: Additional, deeper LCO optical r band upper limit
  30. GRB 251122A / EP251122a: LCO optical upper limits
  31. EP251122a / GRB 251122A: optical counterpart candidate with Kinder observations
  32. EP251122a: Global MASTER-Net observations report
  33. GRB 251122A/EP251122a: SVOM/C-GFT upper limit
  34. GRB 251122A / EP251122a: SVOM detection of a long burst
  35. EP251118a: Continued Optical Detection with Kinder observations
  36. LIGO/Virgo/KAGRA S251105aj: SVOM/ECLAIRs detection of a high-energy transient SVOM J2320.0-2901 through targeted search
  37. LIGO/Virgo/KAGRA S251112cm: SOAR spectroscopy of three TROVE TNS candidates
  38. GRB 251121A: Swift/BAT-GUANO localization skymap of a short burst
  39. GRB 251121A: Glowbug gamma-ray detection of a likely short burst
  40. EP251118a: Xinglong-2.16m optical observation
  41. GRB 251115A: Fermi GBM Observation
  42. EP251118A: 1.3m DFOT optical afterglow detection
  43. GRB 251118A: Swift/UVOT Detection
  44. EP251118a / GRB 251118C: SAO RAS optical observations
  45. GRB 251118A: Glowbug gamma-ray detection
  46. GRB 251118A: Fermi GBM Observation
  47. GRB 251103A: SVOM/ECLAIRs and SVOM/GRM joint refined analysis
  48. EP251118a: Optical detection with Kinder observations
  49. GRB 251118A: GECAM-B detection
  50. LIGO/Virgo/KAGRA S251112cm: SVOM/VT optical observations and preliminary results
  51. EP251118a / GRB 251118C: SVOM/VT optical observation
  52. GRB 251118A: NuSTAR detection of bright prompt emission
  53. EP251118a / GRB 251118C: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at CTIO
  54. GRB 251116C: NOT optical observations
  55. GRB 251118C: Glowbug gamma-ray detection of the fast X-ray transient EP251118A
  56. GRB 251118C: Swift/BAT rates detection of a burst with a possible association with EP 251118A
  57. EP251118A / GRB 251118C : MASTER optical counterpart observations
  58. GRB 251118C: SVOM/GRM observation of a possible gamma-ray counterpart of EP251118a
  59. Konus-Wind detection of GRB 251118C (EP251118a)
  60. EP251118a: FTW optical and NIR observations
  61. GRB 251117A: Insight-HXMT/HE detection
  62. GRB 251119A: SVOM trigger sb25111901 is not a GRB
  63. EP251118a: VLT near-infrared observation
  64. GRB 251116D: SVOM/GRM observation of a long GRB
  65. EP251118a: GOTO optical afterglow detection
  66. EP251118a: NOT spectroscopic redshift of z = 1.216
  67. EP251118a: Global MASTER-Net observations report
  68. EP251118a: preliminary result of EP-FXT follow-up observation
  69. GRB 251118A: Fermi-LAT detection
  70. EP251118a: NOT candidate optical counterpart
  71. GRB 251118A: Swift ToO observations
  72. EP251118a: Einstein Probe detected of a fast X-ray transient
  73. Fermi GRB 251118B: Global MASTER-Net observations report
  74. LIGO/Virgo/KAGRA S251112cm: Upper limits from Glowbug gamma-ray observations
  75. GRB 251117A: FTW Observations of Swift candidate X-ray sources
  76. GRB 251116C: SVOM/ECLAIRs refined analysis
  77. GRB 251116B: SVOM/ECLAIRs refined analysis
  78. GRB 251117A: AstroSat CZTI detection
  79. GRB 251114B: Insight-HXMT/HE detection
  80. GRB 251114B: GECAM-B detection of a short burst
  81. GRB 251117A: Fermi GBM observation
  82. GRB 251013C: Koshka, SAO RAS, Mondy, and CrAO optical observations, possible SN detection
  83. LIGO/Virgo/KAGRA S251117dq: Updated Sky localization
  84. GRB 251116D: Insight-HXMT/HE detection
  85. GRB 251117A: Swift/BAT-GUANO localization skymap of a short burst
  86. GRB 251117A: SVOM/GRM observation of a short burst
  87. GRB 251117A: Tiled Swift observations
  88. GRB 251117A: Fermi-LAT detection
  89. LIGO/Virgo/KAGRA S251117dq: Identification of a GW compact binary merger candidate
  90. GRB 251116C: Swift/BAT arcminute localization of a burst
  91. LIGO/Virgo/KAGRA S251112cm: J-GEM follow-up observations
  92. LIGO/Virgo/KAGRA S251112cm: Classification of reported candidates with SOAR/Goodman
  93. GRB 251116B: SVOM/VT optical upper limit
  94. LIGO/Virgo/KAGRA S251112cm: WFST follow-up observations and preliminary results
  95. LIGO/Virgo/KAGRA S251116en: Updated Sky localization
  96. GRB 251116D: Glowbug gamma-ray detection
  97. EP251023a: Assy AZT-20 optical observations
  98. EP251023a: UAFO and AbAO optical observations
  99. LIGO/Virgo/KAGRA S251112cm: EP-FXT follow-up observations
  100. The EP-WXT trigger 01709247588: more evidence of flaring star from Mondy optical observations

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