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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.

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10956 results found.

  1. GRB 250901A: EP-FXT follow-up observation
  2. EP250827b: Gemini Spectroscopy of AT 2025wkm
  3. EP250831a: NOT optical observations and tentative afterglow candidate
  4. LIGO/Virgo/KAGRA S250831cc: Coverage and upper limits from MAXI/GSC observations
  5. LIGO/Virgo/KAGRA S250830bp: Coverage and upper limits from MAXI/GSC observations
  6. EP-WXT trigger 01709200994: Liverpool Telescope upper limits
  7. GRB 250830B: MAXI/GSC detection
  8. GRB 250830A / MAXI J0853+337: MAXI/GSC detection
  9. EP250828a: Optical counterpart detection with Kinder observations
  10. EP250828a: SVOM/VT optical candidate
  11. EP250828a: Optical upper limit with Kinder observations
  12. EP250827A: VLT/X-shooter redshift confirmation
  13. GRB 250806A: HiPERCAM/GTC limits on a possible supernova
  14. LIGO/Virgo/KAGRA S250818k: SAO RAS BTA z-band observations of AT2025ulz
  15. LIGO/Virgo/KAGRA S250818k: MASTER predicovery limits of the AT2025ulz/ZTF25abjmnps KN candidate
  16. GRB 250823A: SVOM/VT optical observation
  17. GRB 250823A: Swift detection of a burst
  18. LIGO/Virgo/KAGRA S250818k: Rebrightening detected with Gemini/GMOS
  19. LIGO/Virgo/KAGRA S250818k: J-GEM follow-up observation for AT2025ulz
  20. LIGO/Virgo/KAGRA S250818k: PRIME nIR observations of AT2025ulz
  21. EP250821a: VLT X-shooter spectroscopic redshift z = 0.577
  22. LIGO/Virgo/KAGRA S250818k: GRAWITA TNG NIR observations of AT2025ulz
  23. EP250821a: SVOM/VT optical observation
  24. GRB 250814A: CMO SAI and SAO RAS izJ observations.
  25. LIGO/Virgo/KAGRA S250818k: WFST pre-discovery limits and follow-up observations of AT 2025ulz
  26. LIGO/Virgo/KAGRA S250818k: Multi-band Gemini GMOS Detections
  27. LIGO/Virgo/KAGRA S250818k: ATLAS pre-discovery limits for AT2025ulz
  28. GRB 250818B: optical afterglow detection with Lesedi (GOTO25fzq)
  29. GRB 250818B: Keck redshift of the optical afterglow
  30. LIGO/Virgo/KAGRA S250818k: Coverage and upper limits from MAXI/GSC observations
  31. GRB 250818B: SVOM/VT optical observation
  32. GRB 250813B: Liverpool Telescope optical upper limits
  33. GRB 250814A: detection of the afterglow candidate with Liverpool Telescope
  34. GRB 250812A: SVOM/VT optical continued observation
  35. GRB 250814A: Mondy optical observations of the candidate counterpart to LVK S250814bg
  36. LIGO/Virgo/KAGRA S250813k: Swift XRT observations, 2 X-ray sources
  37. GRB 250813B: SVOM/VT optical observations
  38. GRB 250813B: VLT X-shooter spectroscopic redshift z = 1.752
  39. GRB 250812A: NTT spectroscopic redshift z = 2.57
  40. EP250812a: NOT, NTT, and GS observations
  41. EP250812a: SVOM/VT optical counterpart
  42. GRB 250807B: Swift-BAT refined analysis
  43. GRB 250812A: SVOM/VT optical afterglow confirmation
  44. GRB 250807A: Swift-BAT refined analysis
  45. GRB 250807B: SVOM/VT optical observation
  46. GRB 250808A: VLT X-shooter candidate counterpart
  47. GRB 250807A: SVOM/VT optical continued observation
  48. GRB 250808A: SVOM detection of a long burst
  49. GRB 250807B: Swift/UVOT Detection
  50. GRB 250807A: Swift/UVOT Detection
  51. GRB 250807B: VLT/X-Shooter spectroscopic redshift z = 1.522
  52. GRB 250806A: SVOM/ECLAIRs refined analysis
  53. GRB 250806A: Mondy optical observations, and nearby bright galaxy photometry
  54. GRB 250807A: SVOM/GRM observation
  55. GRB 250807A: AstroSat CZTI detection of bright long burst
  56. GRB 250807B: NTT optical observations
  57. GRB 250807A: SVOM/VT optical observation
  58. GRB 250807B: Swift detection of a burst with an optical counterpart.
  59. EP250806a:SVOM/VT refined analysis
  60. EP250806a: Liverpool telescope optical upper limit
  61. GRB 250807A: Swift detection of a burst with an optical counterpart
  62. GRB 250806A: EP-FXT observation
  63. EP250806a: refined analysis of the EP-WXT and EP-FXT observations
  64. EP250806a: SVOM /VT optical candidate
  65. GRB 250806A: SVOM/VT refined analysis
  66. GRB 250805A: SVOM/VT optical counterpart
  67. GRB 250805A: ESO/VLT observations
  68. EP250802a: additional Liverpool Telescope upper limits
  69. EP250730a: SVOM/VT optical upper limit
  70. GRB 250702B: SMA observations
  71. LIGO/Virgo/KAGRA S250725j: GOTO pre-trigger detection of AT2025sib
  72. EP250711a: CrAO and Assy optical observations
  73. LIGO/Virgo/KAGRA S250727dc: DECam DESGW Epoch 1 Candidates
  74. LIGO/Virgo/KAGRA S250725j: DECam DESGW Epoch 1-2 Candidates
  75. LIGO/Virgo/KAGRA S250727dc: Swift-XRT observations, 8 X-ray sources
  76. GRB 250725A: PRIME near-infrared observations
  77. LIGO/Virgo/KAGRA S250727dc: PRIME J-band upper limits of AT 2025smm
  78. GRB 250727A: SVOM/ECLAIRs refined analysis
  79. GRB250727A: SVOM/VT optical upper limit
  80. GRB 250725A: VLT/FORS2 spectroscopic redshift z = 5.26
  81. GRB 250725A: SVOM/VT optical candidate
  82. GRB 250725A: Swift detection of a burst
  83. EP250702a/GRB250702 B,E,D: MeerKAT radio observations at 3.06 GHz
  84. SVOM J195836+32283/sb25072103: Liverpool Telescope detection of an extended source
  85. The SVOM alert sb25072103 is not due to a GRB, but to a new galactic transient SVOM J195836+32283.
  86. GRB 250721A: MAXI/GSC detection
  87. EP250702a/GRB250702B,D,E: SVOM/VT optical upper limit
  88. GRB 270713A: Kitab and AbAO Optical Observations
  89. EP250702a / GRB 250702B,D,E: Hubble Space Telescope Observations
  90. GRB 250713A: SVOM/VT optical upper limit
  91. GRB 250713A: NOT optical upper limits
  92. GRB 250702F: Swift-BAT refined analysis
  93. GRB 250704A: GRANDMA observations
  94. GRB 250704A: SVOM/ECLAIRs refined analysis
  95. GRB 250704B: CALET Gamma-Ray Burst Monitor detection
  96. GRB 250704B / EP250704a: Mondy and AbAO optical observations
  97. GRB 250702F: radio detection with the VLA
  98. GRB 250706B/C: VLT/X-shooter redshift z = 0.942
  99. GRB 250706B/C: Fermi-LAT detection
  100. EP250702a/GRB250702 B,D,E: GRANDMA Upper Limit

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