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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"

3797 results found.

  1. LIGO/Virgo S190930s: No counterpart candidates in KAIT observations
  2. Fermi trigger No 591604915: Global MASTER-Net observations report
  3. LIGO/Virgo S190930t: Coverage and upper limits from MAXI/GSC observations
  4. LIGO/Virgo S190930s: Coverage and upper limits from MAXI/GSC observations
  5. Konus-Wind observation of GRB 190928A
  6. LIGO/Virgo S190923y: No significant candidates in TAROT-GRANDMA observations
  7. LIGO/Virgo S190924h: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  8. LIGO/Virgo S190924h: Coverage and upper limits from MAXI/GSC observations
  9. LIGO/Virgo S190923y: Coverage and upper limits from MAXI/GSC observations
  10. Baksan Neutrino Observatory Alert 190920.65: Global MASTER-Net observations report
  11. Integral GRB190919.99: Global MASTER-Net observations report
  12. LIGO/Virgo S190915ak: No significant candidates in TAROT-GRANDMA observations
  13. LIGO/Virgo S190910h: No significant candidates in TAROT-GRANDMA observations
  14. LIGO/Virgo S190915ak: No transient candidates in CALET observations
  15. Fermi trigger No 590335819: Global MASTER-Net observations report
  16. LIGO/Virgo S190915ak: no counterpart candidates in the Swift/BAT observations
  17. LIGO/Virgo S190915ak: No counterpart candidates in Fermi-LAT observations
  18. LIGO/Virgo S190915ak: Coverage and upper limits from MAXI/GSC observations
  19. GRB190915A: MASTER optical observation of BALROG Fermi GRB localization
  20. LIGO/Virgo S190915ak : no neutrino counterpart candidate in ANTARES search
  21. LIGO/Virgo S190915ak: Upper Limits from AGILE-GRID observations
  22. LIGO/Virgo S190915ak: No counterpart candidate in AGILE-MCAL observations
  23. LIGO/Virgo S190915ak: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  24. LIGO/Virgo S190915ak: Identification of a GW compact binary merger candidate
  25. GRB 190915A: BALROG localization (Fermi Trigger 590219102 / GRB 190915240)
  26. GRB 190915A: Fermi GBM Final Real-time Localization
  27. LIGO/Virgo S190910d : No significant candidates in TAROT-GRANDMA observations
  28. LIGO/Virgo S190814bv: No counterpart candidate after completion of GRAWITA VST-ESO PARANAL transient survey.
  29. LIGO/Virgo S190910d and S190910h: No counterpart candidates in KAIT observations
  30. LIGO/Virgo S190910h: Coverage and upper limits from MAXI/GSC observations
  31. LIGO/Virgo S190910h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  32. Swift Trigger 924641 is an outburst from MAXI J1807+132
  33. LIGO/Virgo S190910d: Coverage and upper limits from MAXI/GSC observations
  34. LIGO/Virgo S190901ap: Gaia Photometric Alerts transient candidates
  35. LIGO/Virgo S190901ap : No significant candidates found in GRANDMA citizen science observations
  36. GRB 190823A: Swift-XRT afterglow detection
  37. GRB 190829A: GTC confirmation of an associated Type Ic-BL Supernova
  38. Fermi trigger No 589419513 Global MASTER-Net observations report
  39. LIGO/Virgo S190901ap : No significant candidates in TAROT-GRANDMA
  40. LIGO/Virgo S190901ap: No counterpart candidates in KAIT observations
  41. LIGO/Virgo S190901ap : GRAWITA photometric observation of candidate ZTFabvizsw and GCN 25618 revision
  42. LIGO/Virgo S190901ap: no counterpart candidate in the SVOM/GWAC observations
  43. LIGO/Virgo S190901ap: Upper limits from Insight-HXMT/HE observations
  44. Liverpool Telescope observations of ZTF19abvizsw, a candidate untriggered GRB afterglow
  45. LIGO/Virgo S190901ap: Coverage and upper limits from MAXI/GSC observations
  46. LIGO/Virgo S190828j : No significant candidates in TAROT-GRANDMA observations
  47. LIGO/Virgo S190828l: No significant candidates in TAROT-GRANDMA observations
  48. GRB 190829A: NOEMA detection of the mm afterglow
  49. GRB 190831A: Fermi GBM Final Real-time Localization
  50. GRB 190829A, Swift-BAT refined analysis
  51. GRB 190829A:: Global MASTER-net optical clear and polarization observations scheduler and some spiculations
  52. GRB 190829A: GROND detection of the Optical/NIR Afterglow
  53. GRB 190829A: Enhanced Swift-XRT position
  54. LIGO/Virgo S190828j: No Counterparts in DDOTI/OAN Optical Observations
  55. LIGO/Virgo S190828l: No counterpart candidates in KAIT observations
  56. GRB 190829A: Dabancheng-0.5m optical afterglow detection
  57. GRB 190829A: Swift detection of a burst consistent with a galaxy at z=0.08
  58. GRB 190828A: Swift-XRT observations
  59. LIGO/Virgo S190828j: No counterpart candidates in KAIT observations
  60. GRB 190828A: Tiled Swift observations
  61. LIGO/Virgo S190828l: Coverage and upper limits from MAXI/GSC observations
  62. LIGO/Virgo S190828j: Coverage and upper limits from MAXI/GSC observations
  63. GRB 190828A: MAXI/GSC detection
  64. GRB 190823A: Swift-XRT observations
  65. LIGO/Virgo S190814bv: MASTER prediscovery and postdiscovery observations DECam candidate DG19wxnjc/AT2019npv field
  66. Fermi trigger No 588350802 Global MASTER-Net observations report
  67. GRB 190823A: Tiled Swift observations
  68. GRB 190823A: MAXI/GSC detection
  69. Fermi trigger No 588185734 Global MASTER-Net observations report
  70. Fermi GBM-190816: Coverage and upper limits from MAXI/GSC observations
  71. Fermi GBM-190816: MASTER-Net optical observation report
  72. LIGO/Virgo S190814bv: No radio counterpart detected in ASKAP observations
  73. LIGO/Virgo S190814bv: No Optical Counterpart Candidates in Second-Epoch Lick/KAIT Observations
  74. LIGO/Virgo S190814bv: RATIR Optical observations of DECam transients
  75. LIGO/Virgo S190814bv : No Counterpart Candidates in Continued Galaxy Targeted Search with Magellan
  76. LIGO/Virgo S190814bv: No candidates from DCT galaxy targeted search and observations of DECam-GROWTH candidates
  77. LIGO/Virgo S190814bv : No Counterpart Candidates in Galaxy Targeted Search with Magellan
  78. Fermi trigger No 587505927 Global MASTER-Net observations report
  79. LIGO/Virgo S190814bv: No counterpart candidates in KAIT observations
  80. LIGO/Virgo S190814bv Global MASTER-Net optical observations
  81. LIGO/Virgo S190814bv: Coverage and upper limits from MAXI/GSC observations
  82. LIGO/Virgo S190814bv: Nordic Optical Telescope imaging of selected galaxies
  83. Fermi trigger No 587392154 Global MASTER-Net observations report
  84. IPN triangulation of GRB 190805B
  85. LIGO/Virgo S190808ae: Coverage and upper limits from MAXI/GSC observations
  86. LIGO/Virgo S190808ae: Identification of a GW compact binary merger candidate
  87. GRB 190805B: AstroSat CZTI detection
  88. GRB 190804B: Swift-XRT afterglow detection
  89. Konus-Wind observation of GRB 190805B
  90. GRB 190805B: Swift-XRT observations
  91. Fermi trigger No 586676451 Global MASTER-Net observations report
  92. GRB 190805B: Fermi GBM detection
  93. GRB 190805B: Tiled Swift observations
  94. GRB 190804B: Swift-XRT observations
  95. GRB 190805B: MAXI/GSC detection
  96. MAXI GRB190804.33 Global MASTER-Net observations report
  97. GRB 190804B: Tiled Swift observations
  98. GRB 190804B: MAXI/GSC detection
  99. Fermi trigger No 586574612 Global MASTER-Net observations report
  100. IPN Triangulation of GRB 190731A

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