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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. 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').

10039 results found.

  1. GRB 250103A: Redshift 4.01 from OSIRIS+/GTC
  2. GRB 250103A: TSHAO optical upper limit
  3. GRB 250103B: Swift detection of a burst
  4. EP241231b: optical upper limit with the Liverpool Telescope
  5. GRB 250101A: Xinglong-2.16m spectroscopic redshift
  6. LIGO/Virgo/KAGRA S241231du: Coverage and upper limit from MAXI/GSC observations
  7. GRB 241229B: Continued CrAO ZTSh observations
  8. GRB 241229B: CrAO ZTSh possible optical counterpart of SVOM/VT confirmation
  9. GRB241229B: UVOT upper limits
  10. GRB 241228A: Mondy optical afterglow observations
  11. GRB 241228B: VLT/X-shooter redshift of z = 2.674
  12. GRB 241229B: Swift detection of a burst
  13. GRB 241228A: Swift/UVOT Upper Limits
  14. GRB 241228A: Swift detection of a burst
  15. LIGO/Virgo/KAGRA S241225c: Two counterpart neutrino candidates from IceCube neutrino searches
  16. GRB 241223A: GRBAlpha detection
  17. GRB 241212A: VZLUSAT-2 detection
  18. EP241223a: Mondy AZT-33IK optical observations
  19. GRB 241029A: AbAO AS-32 optical observations
  20. GRB 241105A: JWST photometric observations of the host galaxy
  21. GRB 241209B: host galaxy detection and GTC/OSIRIS+ spectroscopy
  22. GRB 241218A: Mondy AZT-33IK optical upper limit
  23. GRB 241217A/EP241217b: tentative VLT spectroscopic redshift z=1.879
  24. EP241217a: optical upper limit with the Liverpool Telescope
  25. GRB 241209B: EP-FXT afterglow detection
  26. GRB 241217A / EP241217B: GRANDMA/T1MPicduMidi optical upperlimits
  27. GRB 241217A: refined SVOM/MXT data analysis. Long lasting X-ray emission.
  28. GRB 241218A: Swift detection of a burst
  29. GRB 241217A: GRANDMA/TAROT optical upperlimits
  30. EP241217a: Gemini-North spectroscopic redshift z = 4.59
  31. EP241217a: Kinder optical follow-up observations
  32. GRB 241214A: GRBAlpha detection
  33. GRB 241213A (EP241213a): GRBAlpha detection
  34. GRB 241209D: GRBAlpha detection
  35. GRB 241215A: Mondy AZT-33IK optical observations
  36. The EP-WXT trigger 01709128948 is likely a flaring star
  37. GRB 241209D: CALET Gamma-Ray Burst Monitor detection
  38. GRB 241213B: CALET Gamma-Ray Burst Monitor detection
  39. GRB 241213B: MAXI/GSC detection
  40. GRB 241209B: GRANDMA/TRT upper limit
  41. GRB 241207A: TSHAO Zeiss-1000 optical observations
  42. GRB 241209B: Mondy AZT-33IK and AbAO AS-32 optical observations
  43. GRB 241207A: EIRSAT-1 GMOD Detection
  44. GRB 241209A: Redshift of the likely host galaxy z = 0.784 from OSIRIS+/GTC
  45. GRB 241209B: GRBAlpha detection
  46. GRB 241206C: GRBAlpha detection
  47. EP241208a: Optical upper limit with Kinder observations
  48. GRB 241128A: CrAO ZTSh and Mondy AZT-33IK optical observations
  49. GRB 241209A: VLT/HAWK-I near-IR counterpart candidate
  50. GRB 241209A: GRANDMA/TAROT upper limit
  51. GRB 241209A: VLT/X-shooter spectroscopy
  52. GRB 241114B: cubesat Avion detection
  53. GRB 241209A: VLT optical observations
  54. GRB 241209A: GOTO optical upper limits
  55. GRB 241209B: SVOM/ECLAIRs and GRM detection of a long burst
  56. GRB 241207C: MAXI/GSC detection
  57. GRB 241206B: SVOM/MXT observations: a probable flare from the QSO 1ES 1959+650
  58. EP241113a: Keck/LRIS spectroscopic observation and tentative redshift
  59. GRB 241130A: CALET Gamma-Ray Burst Monitor detection
  60. GRB 241128A : RAPAS follow-up observations
  61. GRB 241201A: GRBAlpha detection
  62. EP241202b: Kinder optical counterpart candidate
  63. GRB 241113B : RAPAS follow-up observation
  64. GRB 241130A: EIRSAT-1 GMOD Detection
  65. EP241201a: Kinder optical counterpart candidate
  66. The EP-WXT trigger 01709126243 is not a real source
  67. LIGO/Virgo/KAGRA S241125n: GRANDMA Optical Upper Limits
  68. GRB 241128A: AbAO optical upper limit
  69. GRB 241128A: Mondy optical observations
  70. GRB 241128A: GRANDMA and Kilonova-Catcher Optical Afterglow Detections and Upperlimits
  71. LIGO/Virgo S241127aj: GRANDMA/FRAM-CTA-N Observations
  72. GRB 241127A: GRANDMA and Kilonova-Catcher optical afterglow detections
  73. LIGO/Virgo/KAGRA S241125n: Preliminary flux estimate and spectral analysis of the Swift/BAT-GUANO candidate counterpart
  74. LIGO/Virgo/KAGRA S241125n: Swift-UVOT Upper Limits
  75. EP241126a: Optical Upper limits with Kinder observations
  76. LIGO/Virgo/KAGRA S241125n: SAGUARO follow-up observations with the MMT
  77. GRB 241113B: EP-FXT afterglow detection
  78. LIGO/Virgo S241125n: Swift XRT observations, 5 X-ray sources
  79. GRB 241026A: radio detection with the VLA
  80. EP241125a: Optical upper limit with Kinder observations
  81. EP241125a: EP detection of an X-ray transient
  82. LIGO/Virgo/KAGRA S241125n: No counterpart candidates in INTEGRAL SPI-ACS prompt observation, comparisong with Swift/BAT counterpart
  83. GRB 241120A: GRBAlpha detection
  84. GRB 241026A: VIRT Optical Upper Limit
  85. GRB 241025A: VIRT Optical Upper Limit
  86. GRB 241120A: CALET Gamma-Ray Burst Monitor detection
  87. EP241021a and EP241026b: Keck/LRIS spectroscopic observations
  88. GRB 241120A: Mondy and AbAO optical observations
  89. EP241119a: Optical upper limits with Kinder observations
  90. GRB 241115A: CALET Gamma-Ray Burst Monitor detection
  91. EP241115a/GRB 241115D: Optical upper limits with Kinder observations
  92. EP241115a/GRB 241115D: Swift/XRT follow-up observation
  93. LIGO/Virgo/KAGRA S241114bi: Coverage and upper limits from MAXI/GSC observations
  94. GRB 241112B: AbAO optical upper limit
  95. LIGO/Virgo/KAGRA S241109bn: ATLAS observations and discovery of the potential counterpart AT2024aawt
  96. GRB 241105A: VLT/FORS2 refined spectroscopic redshift z = 2.681
  97. GRB 241025C: VZLUSAT-2 detection
  98. GRB 241025A: VZLUSAT-2 detection
  99. GRB 241018A: cubesat Avion detection
  100. LIGO/Virgo/KAGRA S241109bn: Coverage and upper limits from MAXI/GSC observations

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