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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.

"N/A_MC170405_R1" does not adhere to advanced search syntax. Please refer to the documentation and try again.
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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subject:"Swift"
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10956 results found.

  1. EP260527a: SVOM/VT optical observation
  2. GRB 260524A: SVOM/ECLAIRs detection of a burst through on-ground search
  3. EP-WXT 01709266106: NOT optical upper limits
  4. GRB 260421B: radio detection with the VLA
  5. GRB 260509A: CrAO ZTSh optical upper limit
  6. GRB 260516D: GOTO optical counterpart detection
  7. GRB 260516D: GTC/OSIRIS+ spectroscopic redshift z = 1.801
  8. GRB 260516D: SVOM/VT optical bright candidate
  9. GRB 260515A: CrAO ZTSh BVRI optical observations
  10. EP260514a: SVOM/VT optical candidate
  11. GRB 260515A: SVOM/VT optical observations
  12. GRB 260515A: GTC/OSIRIS+ spectroscopic redshift z = 0.764
  13. GRB 260510C: CALET Gamma-Ray Burst Monitor detection
  14. GRB 260509A: SVOM/VT optical observations
  15. GRB 260511A: EP-FXT follow-up observation
  16. GRB 260511B: EP-FXT follow-up observation
  17. GRB 260511A: SVOM/VT optical observations
  18. GRB 260511B: SVOM/VT optical observations
  19. GRB 260511B: OSIRIS+/GTC redshift z=2.006
  20. GRB 260510B: SVOM/ECLAIRs refined analysis
  21. GRB 260511B : MITSuME Akeno optical afterglow candidate detection
  22. GRB 260510C: SVOM/VT optical counterpart confirmation
  23. GRB 260510B: SVOM/VT optical upper limits
  24. GRB 260510C: SVOM/VT optical upper limits
  25. GRB 260510C: MAXI/GSC detection
  26. GRB 260510C: SVOM detection of a burst
  27. GRB 260510B: SVOM detection of a burst
  28. GRB 260509A: NOT spectroscopic redshift upper limit z < 1.95
  29. EP260507a: SVOM/VT optical observations
  30. EP260507a: Kinder optical counterpart candidate
  31. EP260507a: LCO optical counterpart
  32. GRB 260504B: SVOM/ECLAIRs refined analysis
  33. GRB 260504B: SVOM/VT optical upper limits
  34. GRB 260421B: radio observation with the VLA
  35. GRB 260310A / AT2026fgk: photometric monitoring and tentative maximum of a possible SN
  36. EP260416a: Mondy and Terskol optical upper limits
  37. EP260321a/SN 2026gzf: spectroscopy at Mondy observatory
  38. GRB 260401A: cubesat Avion detection
  39. The EP-WXT trigger 01709258652: Mondy optical observations
  40. GRB 250328A: VLT host galaxy discovery and redshift z = 1.250
  41. EP260416a: Mondy optical observations
  42. EP260416a: ZTSh R band observations
  43. EP250512a / GRB 250512B: VLT/X-shooter host galaxy identification and redshift z = 1.773
  44. GRB 250530A: VLT/X-shooter host galaxy redshift z = 1.486
  45. GRB 260421B: SVOM/VT optical observations
  46. GRB 260415A: CALET Gamma-Ray Burst Monitor detection
  47. GRB 260415B: CALET Gamma-Ray Burst Monitor detection
  48. GRB 260421B: VLT/X-shooter spectroscopic redshift z = 2.115
  49. EP260416a: Optical follow-up observations with Kinder
  50. GOTO26djh/AT2026jpw: CrAO and Mondy optical observations of the transient
  51. EP260416a: VLT/FORS2 spectroscopic redshift confirmation
  52. GOTO26djh/AT2026jpw: ZTSh R,I bands observations of the transient
  53. EP260416a: SVOM/VT optical observation
  54. GOTO26djh/AT2026jpw: SVOM/VT optical observation
  55. GOTO26djh/AT2026jpw transient: SAO RAS optical observations
  56. NOT r-band observations of the transient GOTO26djh/AT2026jpw
  57. EP260321a: CMO SAI J,K observations
  58. EP260321a: SVOM/VT optical observations and color changes around peak
  59. GRB 260410A: CALET Gamma-Ray Burst Monitor detection
  60. The EP-WXT trigger 01709260010 is likely a flaring star
  61. GRB 260411B: Fermi-LAT detection
  62. EP-WXT01709259790: Optical Upper limits with kinder observations
  63. EP260409a: SVOM/VT optical upper limits
  64. GRB 260407A: CALET Gamma-Ray Burst Monitor detection
  65. EP260321a: VLA radio detection
  66. EP260405a: GMOS-N optical upper limits
  67. EP260405a: SVOM/VT optical upper limits
  68. GRB 260330B: SVOM/VT further optical observation
  69. EP260403a: LCO optical observations of the counterpart
  70. GRB 260330B: SVOM/VT optical candidate
  71. GRB 260402A / EP260402a: SVOM/VT optical upper limits
  72. GRB 260401A: CALET Gamma-Ray Burst Monitor detection
  73. GRB 260401A: MAXI/GSC detection
  74. EP260329b: Mondy and Assy-Turgen optical upper limits
  75. GRB 260330B: SVOM/VT optical upper limits
  76. EP260329b: Optical follow-up with Kinder observations
  77. EP260329a: Optical upper limit with Kinder observations
  78. EP260327a: SVOM/VT optical upper limits
  79. EP260327a: Gemini-North optical upper limits
  80. GRB 260310A: OSIRIS+/GTC spectroscopic detection of the associated BL-Ic, SN 2026fgk
  81. GRB 260310A / AT2026fgk: Late-time infrared detection with MIRAGE on the MDM 1.3m telescope
  82. EP260321a: VLT/FORS2 spectroscopy confirmation of an associated type Ic-BL supernova SN 2026gzf
  83. GRB 260310A: LBT optical observations
  84. EP260321A: Mondy optical observations
  85. GRB 260316B: CALET Gamma-Ray Burst Monitor detection
  86. EP260321a / AT2026gzf: VLT/X-shooter detection of supernova-like spectral features at z = 0.0344
  87. EP260321a: Continued brightening from Kinder follow-up of the emerging supernova candidate
  88. EP260321a: VLT imaging and spectroscopy show the variable source to be at z = 0.0343
  89. EP260321a: further Kinder optical observations
  90. GRB 260321A: SVOM/VT optical upper limits
  91. EP260321a: SVOM/VT optical upper limit
  92. GRB 260310A: continued optical observation at Mondy
  93. EP260321a: Kinder observations detect a blue variable star and set limits on a source from the z =0.034 galaxy within the error circle
  94. GRB 260310A: no evidence of re-brightening up to 9.6 days in optical observation at Mondy
  95. GRB 260310A/AT2026fgk: LBT near-infrared observations
  96. GRB 260310A / AT 2026fgk: radio detection with the VLA
  97. GRB 260310A / AT2026fgk: SVOM/VT optical observations
  98. IceCube-260315A/AT2026fpm: EP-FXT follow-up observation
  99. EP260316a / GRB 260316A: SVOM/VT optical upper limits
  100. EP260316a: optical upper limit with Kinder observations

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