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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"

32736 results found.

  1. EP251130a: KAIT optical observations
  2. EP251130A: Optical observation from 1.3m DFOT
  3. EP251130a: refined analysis of the EP-WXT and EP-FXT observations
  4. EP251130a: JinShan optical observations
  5. Fermi GRB 251130B: Global MASTER-Net observations report
  6. GRB 251127A: SVOM/GRM observation
  7. EP251130a: Swift-XRT counterpart detection
  8. EP251130a: Global MASTER-Net observations report
  9. EP251130a: COLIBRÍ optical counterpart candidate
  10. EP251129a/GRB 251129A: EP-FXT follow-up observations
  11. GRB 251129A / EP251129a: GTC/OSIRIS+ spectroscopic redshift z = 1.460
  12. GRB 251128A: AstroSat CZTI detection
  13. GRB 251129A / EP251129a: SAO RAS optical observations
  14. GRB 251126A: SAO RAS optical observations
  15. GRB 251128A: GECAM-B detection
  16. GRB 251128A: SVOM/GRM observation of a long burst
  17. GRB 251128A: Insight-HXMT/HE detection
  18. SVOM GRB 251129A : MASTER optical counterpart detection
  19. GRB 251129A: Swift-XRT afterglow detection
  20. GRB 251129A: Swift ToO observations
  21. GRB 251129A / EP251129a: SVOM/VT optical fading
  22. EP251129a: Global MASTER-Net observations report
  23. GRB 251129A: Optical Observations via Virtual Telescope Project, Italy
  24. EP251129a/GRB 251129A : Einstein Probe detection of an X-ray transient
  25. GRB 251129A: Correction to the position of the optical counterpar
  26. GRB 251129A: SVOM/VT optical counterpart confirmation with VHF data
  27. GRB 251128A: Fermi GBM Observation
  28. GRB 251129A: SVOM/COLIBRÍ (FM-GFT) optical counterpart candidate
  29. GRB 251126A: Swift-BAT refined analysis
  30. GRB 251126A: TShAO, Mondy, and AbAO optical observations
  31. GRB 251128A: Swift/BAT-GUANO localization skymap of a burst
  32. Fermi GRB 251128A: Global MASTER-Net observations report
  33. GRB 251127A: Glowbug gamma-ray detection
  34. GRB 251126A: OHP/T193 optical observations and tentative spectroscopic redshift
  35. GRB 251126A: further SAO RAS optical observations
  36. GRB 250702B: detection of the compact radio counterpart 139 days after the burst
  37. GRB 251126A NUTTelA-TAO Early Measurements
  38. LIGO/Virgo/KAGRA S251112cm: GECKO/KMTNet tiling observations and transient candidates
  39. GRB251126A: MAO/AZT-22 optical observations
  40. GRB251126A: Continued optical observation from 1.3m DFOT
  41. GRB 251126A: Swift/UVOT Detection
  42. EP251124a: Pan-STARRS ri-band imaging and photometry
  43. GRB 251126A: Mondy and SAO RAS optical observations
  44. GRB 251126A : MITSuME Akeno optical afterglow candidate detection
  45. GRB 251126A: NOT optical observations
  46. GRB 251126A: 1.3m DFOT optical afterglow detection
  47. GRB 251126A: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at McDonald Observatory
  48. GRB 251126A: COLIBRÍ photometric redshift z = 3.5
  49. GRB 251125B: GECAM-B detection
  50. Fermi GRB 251127A: Global MASTER-Net observations report
  51. GRB 251126A: Kilonova-Catcher optical afterglow detection
  52. GRB 251126A: Asiago i-band detection
  53. GRB 251126A: Nanshan/HMT optical afterglow detection
  54. Swift GRB 251126A: Global MASTER-Net observations report
  55. GRB 251121A: Fermi GBM Observation
  56. GRB 251126A: GIT discovery of the likely optical afterglow
  57. GRB 251125B: COLIBRÍ further observations and photometric redshift upper limit of z < 3
  58. EP251124b follow-up observation by EP-FXT
  59. GRB 251125B: COLIBRÍ observations of fading of the MASTER OT candidate
  60. EP251124b: NOT r- and z-band optical upper limits
  61. Fermi GRB 251125B : MASTER OT J155558.56+581224.1 optical counterpart discovery
  62. Fermi GRB 251125B: Global MASTER-Net observations report
  63. EP251124b: Global MASTER-Net observations report
  64. EP251124a: Xinglong GWAC-F60A optical observation
  65. EP251124a (EP-WXT trigger 01709248862) is triggered by the known source AWM 7
  66. Fermi GRB 251125A: Global MASTER-Net observations report
  67. EP251124a: NOT r- and z-band optical upper limits
  68. EP251124a: Global MASTER-Net observations report
  69. GRB 251124A: Fermi GBM Localization by automated pipeline
  70. LIGO/Virgo/KAGRA S251112cm: AT 2025adht Kinder follow-up observations
  71. EP251124a: Optical upper limit with Kinder observations
  72. EP251118A: 6 GHz VLA Detection
  73. Fermi GRB 251124a: Global MASTER-Net observations report
  74. LIGO/Virgo/KAGRA S251105aj: SVOM/VT optical observations and preliminary results on SVOM J2320.0-2901
  75. LIGO/Virgo/KAGRA S251105aj: EP-FXT follow-up observations and preliminary results on SVOM J2320.0-2901
  76. EP251124a: GROWTH-India Telescope optical upper limits
  77. GRB 251116C: Swift-XRT confirmation of fading
  78. GRB 251122A/EP251122a: FTW optical and NIR observations
  79. GRB 251122A/EP251122A: 1.3m DFOT optical detection
  80. GRB 251122A / EP251122a: Xinglong 2.16m optical observation
  81. EP251118A: 3.6m DOT optical afterglow detection
  82. GRB 251122A / EP251122a: EP-FXT counterpart detection
  83. EP251122a: refined analysis of the EP-WXT and EP-FXT observations
  84. GRB 251122A / EP251122a: WFST optical observations
  85. GRB 251122A/EP251122a: SVOM/VT optical observations with VHF data
  86. GRB 251122A/EP251122a: Additional, deeper LCO optical r band upper limit
  87. GRB 251122A / EP251122a: LCO optical upper limits
  88. EP251122a / GRB 251122A: optical counterpart candidate with Kinder observations
  89. EP251122a: Global MASTER-Net observations report
  90. GRB 251122A/EP251122a: SVOM/C-GFT upper limit
  91. GRB 251122A / EP251122a: SVOM detection of a long burst
  92. EP251118a: Continued Optical Detection with Kinder observations
  93. LIGO/Virgo/KAGRA S251105aj: SVOM/ECLAIRs detection of a high-energy transient SVOM J2320.0-2901 through targeted search
  94. LIGO/Virgo/KAGRA S251112cm: SOAR spectroscopy of three TROVE TNS candidates
  95. GRB 251121A: Swift/BAT-GUANO localization skymap of a short burst
  96. GRB 251121A: Glowbug gamma-ray detection of a likely short burst
  97. EP251118a: Xinglong-2.16m optical observation
  98. GRB 251115A: Fermi GBM Observation
  99. EP251118A: 1.3m DFOT optical afterglow detection
  100. GRB 251118A: Swift/UVOT Detection

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