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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').
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28273 results found.

  1. Fermi GRB 250128A: Global MASTER-Net observations report
  2. GRB 250117A: Fermi GBM Observation
  3. Fermi-LAT Gamma-ray Observations of IceCube-250101A
  4. IPN triangulation of GRB 250119C
  5. GRB 250127A: LCO optical upper limit
  6. GRB 241223A: cubesat Avion detection
  7. EP250125A: Non-detection from Fermi-GBM Observations
  8. GRB 250126A: MAXI/GSC detection
  9. GRB 250126A: BALROG localization (Fermi Trigger 759560335 / GRB 250126208)
  10. EP250125a: Optical upper limit with Kinder observations
  11. EP250125a: REM optical counterpart detection
  12. GRB 250119C: Fermi GBM Observation
  13. EP250125a: Swift/XRT detection of a fading counterpart
  14. EP250125a: a new X-ray transient detected by Einstein Probe
  15. EP250125a: Gemini-South optical afterglow discovery and redshift z = 2.89
  16. GRB 250121A: Swift/BAT-GUANO localization skymap of a burst
  17. EP250108a: AbAO, CMO and Terskol optical upper limits
  18. GRB 250121A: Fermi GBM Observation
  19. IPN triangulation of GRB 250118B
  20. IPN triangulation of GRB 250119B
  21. GRB 250114A: Swift-BAT refined analysis
  22. LIGO/Virgo S250119cv: Swift XRT observations, 5 X-ray sources
  23. GRB 250119C: Swift/BAT-GUANO localization skymap of a short burst
  24. GRB 250119B: Swift/BAT-GUANO localization skymap of a long burst
  25. Fermi-LAT Gamma-ray Observations of IceCube-241224A
  26. GRB 250118A: Swift/BAT-GUANO localization skymap of a short burst
  27. GRB 250119B: Fermi GBM Observation
  28. EP250108a/AT2025kg: 1.3m DFOT Optical observations
  29. IPN triangulation of GRB 250117A (short)
  30. LIGO/Virgo/KAGRA S250119cv: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  31. EP 250108A: Late-time optical observation by LCO
  32. LIGO/Virgo/KAGRA S250105bn: 1 counterpart neutrino candidate event from an IceCube neutrino search
  33. LIGO/Virgo/KAGRA S250119cv: Updated NED Galaxies in the Localization Volume
  34. LIGO/Virgo/KAGRA S250119cv: Updated Sky localization and EM Bright Classification
  35. LIGO/Virgo/KAGRA S250119cv: NED Galaxies in the Localization Volume
  36. GRB 250117A: Swift/BAT-GUANO localization skymap of a short burst
  37. LIGO/Virgo/KAGRA S250119cv: Identification of a GW compact binary merger candidate
  38. LIGO/Virgo/KAGRA S250119ag: Updated Sky localization
  39. GRB 250117A: GECAM observation of a short burst
  40. LIGO/Virgo/KAGRA S250118dp: Updated Sky localization
  41. GRB 250119B: BALROG localization (Fermi Trigger 758968026 / GRB 250119352)
  42. LIGO/Virgo/KAGRA S250119ag: Identification of a GW compact binary merger candidate
  43. LIGO/Virgo/KAGRA S250118dp: Identification of a GW compact binary merger candidate
  44. LIGO/Virgo/KAGRA S250118t: Updated Sky localization
  45. LIGO/Virgo/KAGRA S250118az: Identification of a GW compact binary merger candidate
  46. EP250108a / AT2025kg: GMG Optical Observations
  47. LIGO/Virgo/KAGRA S250118t: Identification of a GW compact binary merger candidate
  48. GRB 241217A / EP241217B: radio detection with the VLA
  49. GRB 250116A: Fermi GBM Observation of an Extremely Interesting Burst
  50. GRB 250114B: Swift-XRT afterglow detection
  51. EP250108a: MeerKAT radio upper limit
  52. LIGO/Virgo/KAGRA S250114ax: Updated NED Galaxies in the Localization Volume
  53. GRB 250101A: Calapai Observatory, Massa S. Giorgio (Messina), optical observations and rebrightening.
  54. LIGO/Virgo/KAGRA S250114ax: Updated Sky localization
  55. IPN triangulation of GRB 250113A
  56. GRB 250114B: Liverpool Telescope optical upper limit
  57. LIGO/Virgo/KAGRA S250114ax: GLADEnet Completeness: Potential Host Galaxies in the 90% Credible Volume
  58. GRB 250114B : MITSuME Akeno optical afterglow candidate detection
  59. GRB 250114B: Swift-XRT observations
  60. GRB 250114A: LCO optical counterpart detection.
  61. GRB 250114B: OHP/T193 optical upper limit
  62. GRB 250114A: GRANDMA/TAROT optical afterglow detection
  63. GRB 250114A: Swift-XRT refined Analysis
  64. GRB 250114A: LCOGT optical afterglow i-band detection
  65. GRB 250114B : GIT optical upper limit
  66. EP250111a: SAO RAS optical upper limit
  67. LIGO/Virgo/KAGRA S250114ax: NED Galaxies in the Localization Volume
  68. GRB 250114B: a short GRB detected with INTEGRAL
  69. GRB 250114A: Enhanced Swift-XRT position
  70. GRB 250114A: REM detection of the optical and NIR counterpart
  71. LIGO/Virgo/KAGRA S250114ax: Identification of a GW compact binary merger candidate
  72. Swift GRB250114A: Global MASTER-Net OT detection
  73. GRB 250114A: LCO optical observations
  74. GRB 250114A: TRT optical observations
  75. GRB 250114A: Swift detection of a burst with an optical counterpart
  76. GRB 250101A: Terskol Zeiss-2000 optical observations
  77. EP250108a / AT 2025kg: SAO RAS optical observations
  78. EP241021a: SMA radio observation
  79. GRB 250113A: SVOM/GRM observation of a long burst
  80. GRB 250107A: VZLUSAT-2 detection
  81. EP250109b: optical upper limits with the Liverpool Telescope
  82. GRB 250106A: Swift-XRT afterglow detection
  83. EP250111a: KAIT optical observations
  84. GRB 250109A / EP250109a: Mephisto optical upper limits
  85. EP250108a: Mephisto detection
  86. EP250111a: Mondy optical observation
  87. EP250108a / AT 2025kg: LCO optical observations
  88. EP250108a / AT 2025kg: Swift UVOT detections
  89. EP250108a / AT 2025kg (the "kangaroo”): VLT/X-shooter spectroscopic redshift z = 0.176 and LFBOT classification
  90. EP250111a: NOT likely optical counterpart
  91. GRB 250101B: Fermi GBM Observation
  92. GRB 250109A / EP250109a: Terskol (INASAN) and SAO RAS observations
  93. GRB 250109A / EP250109A: Swift/BAT-GUANO localization skymap of a burst
  94. GRB 250108A: Swift/XRT afterglow fading
  95. LIGO/Virgo/KAGRA S250109bi: Updated Sky localization
  96. LIGO/Virgo/KAGRA S250109f: Updated Sky localization
  97. LIGO/Virgo/KAGRA S250108eo: Updated Sky localization
  98. EP-WXT trigger EP250108a:Xinglong optical follow-up observations
  99. GRB 250101A: CMO RC-500 optical observations
  100. GRB 250109A: Fermi GBM Observation

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