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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"

18484 results found.

  1. SVOM GRB251129A: Global MASTER-Net observations report
  2. GRB 251129A: SVOM detection of a burst
  3. GRB 251126A: TShAO, Mondy, and AbAO optical observations
  4. GRB 251128A: Swift/BAT-GUANO localization skymap of a burst
  5. GRB 251126A: further SAO RAS optical observations
  6. LIGO/Virgo/KAGRA S251112cm: GECKO/KMTNet tiling observations and transient candidates
  7. GRB251126A: MAO/AZT-22 optical observations
  8. GRB251126A: Continued optical observation from 1.3m DFOT
  9. GRB 251126A: Swift/UVOT Detection
  10. GRB 251126A: Mondy and SAO RAS optical observations
  11. GRB 251126A: Swift-XRT refined Analysis
  12. GRB 251126A : MITSuME Akeno optical afterglow candidate detection
  13. GRB 251126A: 1.3m DFOT optical afterglow detection
  14. GRB 251126A: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at McDonald Observatory
  15. GRB 251126A: COLIBRÍ photometric redshift z = 3.5
  16. GRB 251126A: Enhanced Swift-XRT position
  17. GRB 251126A: Kilonova-Catcher optical afterglow detection
  18. GRB 251126A: Nanshan/HMT optical afterglow detection
  19. GRB 251126A: GIT discovery of the likely optical afterglow
  20. GRB 251126A: Swift detection of a burst
  21. GRB 251125B: COLIBRÍ further observations and photometric redshift upper limit of z < 3
  22. EP251124b follow-up observation by EP-FXT
  23. GRB 251125B: COLIBRÍ observations of fading of the MASTER OT candidate
  24. EP251124b: NOT r- and z-band optical upper limits
  25. EP251124b: EP-WXT detection of a fast X-ray transient
  26. EP251124a: Xinglong GWAC-F60A optical observation
  27. EP251124a (EP-WXT trigger 01709248862) is triggered by the known source AWM 7
  28. EP251124a: NOT r- and z-band optical upper limits
  29. EP251124a: Swift-XRT observations
  30. LIGO/Virgo/KAGRA S251112cm: AT 2025adht Kinder follow-up observations
  31. EP251124a: Optical upper limit with Kinder observations
  32. LIGO/Virgo/KAGRA S251105aj: SVOM/VT optical observations and preliminary results on SVOM J2320.0-2901
  33. LIGO/Virgo/KAGRA S251105aj: EP-FXT follow-up observations and preliminary results on SVOM J2320.0-2901
  34. EP251124a: GROWTH-India Telescope optical upper limits
  35. EP251124a: Einstein Probe detection of an X-ray transient
  36. GRB 251116C: Swift-XRT confirmation of fading
  37. GRB 251122A/EP251122A: 1.3m DFOT optical detection
  38. The EP-WXT trigger 01709248783 is likely a flaring star
  39. GRB 251122A / EP251122a: Xinglong 2.16m optical observation
  40. EP251118A: 3.6m DOT optical afterglow detection
  41. GRB 251122A / EP251122a: EP-FXT counterpart detection
  42. EP251122a: refined analysis of the EP-WXT and EP-FXT observations
  43. GRB 251122A / EP251122a: WFST optical observations
  44. GRB 251122A/EP251122a: SVOM/VT optical observations with VHF data
  45. GRB 251122A/EP251122a: Additional, deeper LCO optical r band upper limit
  46. GRB 251122A / EP251122a: LCO optical upper limits
  47. EP251122a / GRB 251122A: optical counterpart candidate with Kinder observations
  48. GRB 251122A/EP251122a: SVOM/C-GFT upper limit
  49. GRB 251122A / EP251122a: SVOM detection of a long burst
  50. EP251122a: Einstein Probe detection of an X-ray transient
  51. EP251118a: Continued Optical Detection with Kinder observations
  52. LIGO/Virgo/KAGRA S251105aj: SVOM/ECLAIRs detection of a high-energy transient SVOM J2320.0-2901 through targeted search
  53. GRB 251121A: Swift/BAT-GUANO localization skymap of a short burst
  54. EP251118a: Xinglong-2.16m optical observation
  55. The EP-WXT trigger 01709248635 is likely a flaring star
  56. EP251118A: 1.3m DFOT optical afterglow detection
  57. GRB 251118A: Swift/UVOT Detection
  58. EP251118a / GRB 251118C: SAO RAS optical observations
  59. GRB 251118A: Swift-XRT afterglow detection
  60. EP251118a: Optical detection with Kinder observations
  61. LIGO/Virgo/KAGRA S251112cm: SVOM/VT optical observations and preliminary results
  62. The EP-WXT trigger 01709248403 is likely a flaring star
  63. GRB 251118A: NuSTAR detection of bright prompt emission
  64. EP251118a / GRB 251118C: ULL-ASTRO-MASTER detection of the optical afterglow with LCO 1-m telescope at CTIO
  65. GRB 251118C: Swift/BAT rates detection of a burst with a possible association with EP 251118A
  66. GRB 251117A: Swift-XRT observations
  67. GRB 251118C: SVOM/GRM observation of a possible gamma-ray counterpart of EP251118a
  68. The EP-WXT trigger 01709248388 is likely a flaring star
  69. GRB 251119A: SVOM trigger sb25111901 is not a GRB
  70. EP251118a: VLT near-infrared observation
  71. GRB 251116D: SVOM/GRM observation of a long GRB
  72. GRB 251119A: SVOM detection of a possible burst
  73. EP251118a: preliminary result of EP-FXT follow-up observation
  74. EP251118a: NOT candidate optical counterpart
  75. EP251118a: Einstein Probe detected of a fast X-ray transient
  76. LIGO/Virgo/KAGRA S251112cm: Upper limits from Glowbug gamma-ray observations
  77. GRB 251117A: Swift/BAT-GUANO localization skymap of a short burst
  78. GRB 251117A: SVOM/GRM observation of a short burst
  79. LIGO/Virgo/KAGRA S251117dq: Identification of a GW compact binary merger candidate
  80. LIGO/Virgo/KAGRA S251112cm: WFST follow-up observations and preliminary results
  81. EP251023a: Assy AZT-20 optical observations
  82. EP251023a: UAFO and AbAO optical observations
  83. LIGO/Virgo/KAGRA S251112cm: EP-FXT follow-up observations
  84. The EP-WXT trigger 01709247588: more evidence of flaring star from Mondy optical observations
  85. GRB 251025B: further Mondy optical observations
  86. GRB 251111A: Mondy optical upper limit
  87. LIGO/Virgo/KAGRA S251116en: Identification of a GW compact binary merger candidate
  88. LIGO/Virgo/KAGRA S251112cm: Observations with the NSF-DOE Vera C. Rubin Observatory
  89. GRB 251116B: LCO optical upper limits
  90. GRB 251116C: LCO optical upper limits
  91. LIGO/Virgo/KAGRA S251112cm: GRANDMA observations of the skymap
  92. LIGO/Virgo/KAGRA S251112cm: DECam GW-MMADS candidates
  93. LIGO/Virgo/KAGRA S251112cm: Swift XRT observations, 20 X-ray sources
  94. The EP-WXT trigger 01709248221 is likely a flaring star
  95. LIGO/Virgo/KAGRA S251112cm: FTW observations of galaxies within localization region
  96. GRB 251112A: Swift/UVOT Upper Limits
  97. GRB 251112A: Swift-XRT refined Analysis
  98. LIGO/Virgo/KAGRA S251112cm: Coverage and upper limits from MAXI/GSC observations
  99. Swift Trigger 1413695: a possible GRB 251112A
  100. GRB251111A: 1.3m DFOT optical upper limit

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