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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').
Advanced Search

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.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

2974 results found.

  1. LIGO/Virgo S190915ak: No significant candidates in TAROT-GRANDMA observations
  2. LIGO/Virgo S190910h: No significant candidates in TAROT-GRANDMA observations
  3. LIGO/Virgo S190915ak: No transient candidates in CALET observations
  4. Fermi trigger No 590335819: Global MASTER-Net observations report
  5. LIGO/Virgo S190915ak: no counterpart candidates in the Swift/BAT observations
  6. LIGO/Virgo S190915ak: No counterpart candidates in Fermi-LAT observations
  7. LIGO/Virgo S190915ak: Coverage and upper limits from MAXI/GSC observations
  8. GRB190915A: MASTER optical observation of BALROG Fermi GRB localization
  9. LIGO/Virgo S190915ak : no neutrino counterpart candidate in ANTARES search
  10. LIGO/Virgo S190915ak: Upper Limits from AGILE-GRID observations
  11. LIGO/Virgo S190915ak: No counterpart candidate in AGILE-MCAL observations
  12. LIGO/Virgo S190915ak: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  13. LIGO/Virgo S190915ak: Identification of a GW compact binary merger candidate
  14. GRB 190915A: BALROG localization (Fermi Trigger 590219102 / GRB 190915240)
  15. GRB 190915A: Fermi GBM Final Real-time Localization
  16. LIGO/Virgo S190910d : No significant candidates in TAROT-GRANDMA observations
  17. LIGO/Virgo S190814bv: No counterpart candidate after completion of GRAWITA VST-ESO PARANAL transient survey.
  18. LIGO/Virgo S190910d and S190910h: No counterpart candidates in KAIT observations
  19. LIGO/Virgo S190910h: Coverage and upper limits from MAXI/GSC observations
  20. LIGO/Virgo S190910h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  21. LIGO/Virgo S190901ap: Gaia Photometric Alerts transient candidates
  22. LIGO/Virgo S190901ap : No significant candidates found in GRANDMA citizen science observations
  23. GRB 190829A: GTC confirmation of an associated Type Ic-BL Supernova
  24. Fermi trigger No 589419513 Global MASTER-Net observations report
  25. LIGO/Virgo S190901ap : No significant candidates in TAROT-GRANDMA
  26. LIGO/Virgo S190901ap: No counterpart candidates in KAIT observations
  27. LIGO/Virgo S190901ap : GRAWITA photometric observation of candidate ZTFabvizsw and GCN 25618 revision
  28. LIGO/Virgo S190901ap: no counterpart candidate in the SVOM/GWAC observations
  29. LIGO/Virgo S190901ap: Upper limits from Insight-HXMT/HE observations
  30. Liverpool Telescope observations of ZTF19abvizsw, a candidate untriggered GRB afterglow
  31. LIGO/Virgo S190828j : No significant candidates in TAROT-GRANDMA observations
  32. LIGO/Virgo S190828l: No significant candidates in TAROT-GRANDMA observations
  33. GRB 190829A: NOEMA detection of the mm afterglow
  34. GRB 190831A: Fermi GBM Final Real-time Localization
  35. GRB 190829A, Swift-BAT refined analysis
  36. GRB 190829A:: Global MASTER-net optical clear and polarization observations scheduler and some spiculations
  37. GRB 190829A: GROND detection of the Optical/NIR Afterglow
  38. GRB 190829A: Enhanced Swift-XRT position
  39. LIGO/Virgo S190828j: No Counterparts in DDOTI/OAN Optical Observations
  40. LIGO/Virgo S190828l: No counterpart candidates in KAIT observations
  41. GRB 190829A: Dabancheng-0.5m optical afterglow detection
  42. GRB 190829A: Swift detection of a burst consistent with a galaxy at z=0.08
  43. LIGO/Virgo S190828j: No counterpart candidates in KAIT observations
  44. GRB 190828A: MAXI/GSC detection
  45. LIGO/Virgo S190814bv: MASTER prediscovery and postdiscovery observations DECam candidate DG19wxnjc/AT2019npv field
  46. Fermi trigger No 588350802 Global MASTER-Net observations report
  47. GRB 190823A: MAXI/GSC detection
  48. Fermi trigger No 588185734 Global MASTER-Net observations report
  49. Fermi GBM-190816: MASTER-Net optical observation report
  50. LIGO/Virgo S190814bv: No radio counterpart detected in ASKAP observations
  51. LIGO/Virgo S190814bv: No Optical Counterpart Candidates in Second-Epoch Lick/KAIT Observations
  52. LIGO/Virgo S190814bv: RATIR Optical observations of DECam transients
  53. LIGO/Virgo S190814bv : No Counterpart Candidates in Continued Galaxy Targeted Search with Magellan
  54. LIGO/Virgo S190814bv: No candidates from DCT galaxy targeted search and observations of DECam-GROWTH candidates
  55. LIGO/Virgo S190814bv : No Counterpart Candidates in Galaxy Targeted Search with Magellan
  56. Fermi trigger No 587505927 Global MASTER-Net observations report
  57. LIGO/Virgo S190814bv: No counterpart candidates in KAIT observations
  58. LIGO/Virgo S190814bv Global MASTER-Net optical observations
  59. LIGO/Virgo S190814bv: Nordic Optical Telescope imaging of selected galaxies
  60. Fermi trigger No 587392154 Global MASTER-Net observations report
  61. LIGO/Virgo S190808ae: Identification of a GW compact binary merger candidate
  62. Fermi trigger No 586676451 Global MASTER-Net observations report
  63. GRB 190805B: MAXI/GSC detection
  64. GRB 190804B: MAXI/GSC detection
  65. Fermi trigger No 586574612 Global MASTER-Net observations report
  66. IPN Triangulation of GRB 190731A
  67. LIGO/Virgo S190728q: No counterpart candidates in KAIT observations
  68. LIGO/Virgo S190728q: no counterpart candidates in AGILE-GRID observations
  69. LIGO/Virgo S190728q Global MASTER-Net observations report
  70. LIGO/Virgo S190727h: No counterpart candidates in KAIT observations
  71. Fermi trigger No 585864875 Global MASTER-Net observations report
  72. Fermi trigger No 585856427 Global MASTER-Net observations report
  73. LIGO/Virgo S190720a: Thacher Observatory follow-up observations
  74. IPN triangulation of GRB 190724A (short)
  75. LIGO/Virgo S190720a: No counterpart candidates in KAIT observations
  76. LIGO/Virgo S190720a: Upper limits from Fermi-GBM Observations
  77. LIGO/Virgo S190718y: No counterpart candidates in CNEOST
  78. LIGO/Virgo S190718y: No counterpart candidates in KAIT observations
  79. Swift GRB190718.2 Global MASTER-Net observations report
  80. Fermi trigger No 585007213 Global MASTER-Net observations report
  81. Fermi trigger No 584929684 Global MASTER-Net observations report
  82. GRB 190714A: MAXI/GSC detection
  83. Fermi trigger No 584637077 Global MASTER-Net observations report
  84. LIGO/Virgo S190706ai: Upper limits from Insight-HXMT/HE observations
  85. MAXI GRB190708.83 Global MASTER-Net observations report
  86. LIGO/Virgo S190706ai: No counterpart candidates in KAIT observations
  87. GRB 190706A: MAXI/GSC detection
  88. Fermi trigger No 584007338 Global MASTER-Net observations report
  89. LIGO/Virgo S190630ag: no counterpart candidate in the SVOM/GWAC observations
  90. GRB 190630C: Swift-BAT refined analysis
  91. GRB 190701A: MAXI/GSC detection
  92. Fermi trigger No 583567803 Global MASTER-Net observations report
  93. GRB 190627A: Koshka Zeiss-1000 optical counterpart observations
  94. Fermi trigger No 583327924 Global MASTER-Net observations report
  95. Fermi trigger No 582856902 Global MASTER-Net observations report
  96. Fermi trigger No 582759998 Global MASTER-Net observations report
  97. Fermi trigger No 582615488 Global MASTER-Net observations report
  98. Fermi trigger No 582115625 Global MASTER-Net observations report
  99. IPN Triangulation of GRB 190611B
  100. GRB 190612A: Fermi GBM Final Real-time Localization

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