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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"

19320 results found.

  1. SVOM GRB251201.19: Global MASTER-Net observations report
  2. EP251130a: SAO RAS optical observations
  3. EP251130a: GTC OSIRIS+ redshift z = 4.035 and rebrightening
  4. EP251130a: refined analysis of the EP-WXT and EP-FXT observations
  5. GRB 251201A: MAXI/GSC detection
  6. Fermi GRB 251130B: Global MASTER-Net observations report
  7. GRB 251127A: SVOM/GRM observation
  8. IceCube Alert 251130.75: Global MASTER-Net observations report
  9. EP251130a: Swift-XRT counterpart detection
  10. EP251130a: Global MASTER-Net observations report
  11. GRB 251126A: SAO RAS optical observations
  12. SVOM GRB 251129A : MASTER optical counterpart detection
  13. GRB 251129A: Swift-XRT afterglow detection
  14. EP251129a: Global MASTER-Net observations report
  15. GRB 251129A: SVOM/VT optical counterpart confirmation with VHF data
  16. GRB 251128A: Fermi GBM Observation
  17. SVOM GRB251129A: Global MASTER-Net observations report
  18. GRB 251126A: Swift-BAT refined analysis
  19. GRB 251128A: Swift/BAT-GUANO localization skymap of a burst
  20. Fermi GRB 251128A: Global MASTER-Net observations report
  21. GRB 251127A: Glowbug gamma-ray detection
  22. GRB 251126A: OHP/T193 optical observations and tentative spectroscopic redshift
  23. GRB 251126A: further SAO RAS optical observations
  24. GRB 251126A NUTTelA-TAO Early Measurements
  25. LIGO/Virgo/KAGRA S251112cm: GECKO/KMTNet tiling observations and transient candidates
  26. GRB 251126A: Swift-XRT refined Analysis
  27. GRB 251126A: NOT optical observations
  28. GRB 251126A: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at McDonald Observatory
  29. GRB 251126A: COLIBRÍ photometric redshift z = 3.5
  30. Fermi GRB 251127A: Global MASTER-Net observations report
  31. GRB 251126A: Enhanced Swift-XRT position
  32. GRB 251126A: Nanshan/HMT optical afterglow detection
  33. Swift GRB 251126A: Global MASTER-Net observations report
  34. GRB 251121A: Fermi GBM Observation
  35. Fermi GRB 251125B : MASTER OT J155558.56+581224.1 optical counterpart discovery
  36. Fermi GRB 251125B: Global MASTER-Net observations report
  37. EP251124b: Global MASTER-Net observations report
  38. EP251124a (EP-WXT trigger 01709248862) is triggered by the known source AWM 7
  39. Fermi GRB 251125A: Global MASTER-Net observations report
  40. EP251124a: Global MASTER-Net observations report
  41. EP251124a: Swift-XRT observations
  42. LIGO/Virgo/KAGRA S251112cm: AT 2025adht Kinder follow-up observations
  43. EP251124a: Optical upper limit with Kinder observations
  44. Fermi GRB 251124a: Global MASTER-Net observations report
  45. LIGO/Virgo/KAGRA S251105aj: SVOM/VT optical observations and preliminary results on SVOM J2320.0-2901
  46. LIGO/Virgo/KAGRA S251105aj: EP-FXT follow-up observations and preliminary results on SVOM J2320.0-2901
  47. EP251124a: Einstein Probe detection of an X-ray transient
  48. GRB 251116C: Swift-XRT confirmation of fading
  49. GRB 251122A / EP251122a: Xinglong 2.16m optical observation
  50. GRB 251122A / EP251122a: EP-FXT counterpart detection
  51. GRB 251122A/EP251122a: SVOM/VT optical observations with VHF data
  52. GRB 251122A / EP251122a: LCO optical upper limits
  53. EP251122a: Global MASTER-Net observations report
  54. GRB 251122A/EP251122a: SVOM/C-GFT upper limit
  55. LIGO/Virgo/KAGRA S251105aj: SVOM/ECLAIRs detection of a high-energy transient SVOM J2320.0-2901 through targeted search
  56. GRB 251121A: Swift/BAT-GUANO localization skymap of a short burst
  57. GRB 251121A: Glowbug gamma-ray detection of a likely short burst
  58. GRB 251115A: Fermi GBM Observation
  59. Fermi trigger No 785388351: Global MASTER-Net observations report
  60. EP251118a / GRB 251118C: SAO RAS optical observations
  61. GRB 251118A: Glowbug gamma-ray detection
  62. GRB 251118A: Fermi GBM Observation
  63. GRB 251118A: Swift-XRT afterglow detection
  64. GRB 251103A: SVOM/ECLAIRs and SVOM/GRM joint refined analysis
  65. EP251118a: Optical detection with Kinder observations
  66. GRB 251118A: NuSTAR detection of bright prompt emission
  67. EP251118a / GRB 251118C: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at CTIO
  68. GRB 251116C: NOT optical observations
  69. GRB 251118C: Glowbug gamma-ray detection of the fast X-ray transient EP251118A
  70. GRB 251118C: Swift/BAT rates detection of a burst with a possible association with EP 251118A
  71. GRB 251117A: Swift-XRT observations
  72. EP251118A / GRB 251118C : MASTER optical counterpart observations
  73. GRB 251118C: SVOM/GRM observation of a possible gamma-ray counterpart of EP251118a
  74. Konus-Wind detection of GRB 251118C (EP251118a)
  75. EP251118a: Global MASTER-Net observations report
  76. LAT GRB251118.86: Global MASTER-Net observations report
  77. EP251118a: Einstein Probe detected of a fast X-ray transient
  78. Fermi GRB 251118B: Global MASTER-Net observations report
  79. LIGO/Virgo/KAGRA S251112cm: Upper limits from Glowbug gamma-ray observations
  80. GRB 251118A: BALROG localization (Fermi Trigger 785190695 / GRB 251118855)
  81. GRB 251117A: AstroSat CZTI detection
  82. GRB 251013C: Koshka, SAO RAS, Mondy, and CrAO optical observations, possible SN detection
  83. LIGO/Virgo/KAGRA S251117dq: Updated Sky localization
  84. GRB 251115A: Swift-XRT observations
  85. GRB 251117A: Swift/BAT-GUANO localization skymap of a short burst
  86. LAT GRB251117.51: Global MASTER-Net observations report
  87. LIGO/Virgo/KAGRA S251117dq: Identification of a GW compact binary merger candidate
  88. LIGO/Virgo/KAGRA S251112cm: J-GEM follow-up observations
  89. GRB 251116C: Swift-XRT observations
  90. LIGO/Virgo/KAGRA S251116en: Updated Sky localization
  91. GRB 251116D: Glowbug gamma-ray detection
  92. GRB 251116D: AstroSat CZTI detection
  93. GRB 251116C: SVOM/VT optical upper limit
  94. GRB 251025B: further Mondy optical observations
  95. GRB 251116B: EP-FXT follow-up observation
  96. LIGO/Virgo/KAGRA S251116en: Identification of a GW compact binary merger candidate
  97. LIGO/Virgo/KAGRA S251112cm: Observations with the NSF-DOE Vera C. Rubin Observatory
  98. SVOM GRB251116C: Global MASTER-Net observations report
  99. GRB 251116B: SVOM detection of a burst
  100. IceCube-Cascade 251112A: Upper limits from a search for additional neutrino events in IceCube

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