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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"

4055 results found.

  1. LIGO/Virgo S200213t: No transient candidates in CALET observations
  2. LIGO/Virgo S200213t: Lulin Follow-Up Observations
  3. GRB 200215A: Nanshan/NEXT optical upper limit
  4. LIGO/Virgo S200213t: MASTER possible Kilonova candidate in PGC315337
  5. LIGO/Virgo S200213t: No neutrino candidates at Pierre Auger Observatory
  6. LIGO/Virgo S200213t: P200 Spectroscopy of ZTF20aanakcd/AT2020cmr
  7. LIGO/Virgo S200213t: DBSP spectroscopy of AT2020cjb/ZTF20aamvnth, AT2020cja/ZTF20aamvmzj, AT2020cjc/ZTF20aamvoeh
  8. LIGO/Virgo S200114f: Gemini Spectra of AT 2020vu, AT 2020vw, AT 2020vy, and AT 2020vz
  9. LIGO/Virgo S200213t: MASTER OT detection in PGC673735
  10. LIGO/Virgo S200213t: Upper limits from Insight-HXMT/HE observations
  11. LIGO/Virgo S200213t: No counterpart candidates from Nanshan-0.6m observations
  12. LIGO/Virgo S200213t: No notable candidates in GOTO imaging
  13. LIGO/Virgo S200213t: One additional candidate from the Zwicky Transient Facility
  14. LIGO/Virgo S200213t: No Counterparts from GECKO observation of host galaxy candidates in GW-neutrino detection overlap area
  15. LIGO/Virgo S200213t: No candidates found in J-GEM follow-up observations
  16. LIGO/Virgo S200213t: More Candidates from the Zwicky Transient Facility
  17. LIGO/Virgo S200213t: No counterpart candidates in KAIT observations
  18. LIGO/Virgo S200213t: AT2020ciz/ZTF20aamvnat, AT2020cjb/ZTF20aamvnth and 2020cjf/ZTF20aamvodd 10.4m GTC spectroscopy
  19. LIGO/Virgo S200213t: No counterpart candidates in Fermi-LAT observations
  20. LIGO/Virgo S200213t: No Counterparts in DDOTI/OAN Optical Observations
  21. LIGO/Virgo S200213t: AT2020ciy/ZTF20aamvqxl, AT2020cjg/ZTF20aamvoxx and AT2020cje/ZTF20aamvtip 10.4m GTC spectroscopy
  22. LIGO/Virgo S200213t: MANGROVE catalog galaxy ranking
  23. LIGO/Virgo S200213t: Swift/BAT in the South Atlantic Anomaly
  24. LIGO/Virgo S191213g: AT2019wxt Wendelstein optical observations
  25. LIGO/Virgo S200213t: not observable by Fermi-GBM
  26. LIGO/Virgo S200213t: upper limits from AGILE/GRID observations
  27. LIGO/Virgo S200208q : No significant candidates in TAROT - FRAM - GRANDMA observations
  28. LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
  29. LIGO/VIRGO S200213t: upper limits from AGILE/MCAL observations
  30. LIGO/Virgo S200213t: Candidates from the Zwicky Transient Facility
  31. LIGO/Virgo S200213t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  32. LIGO/Virgo S200213t : no neutrino counterpart candidate in ANTARES search
  33. LIGO/Virgo S200213t: Coverage and upper limits from MAXI/GSC observations
  34. LIGO/Virgo S200213t: Neutrino and galaxies cross-match
  35. LIGO/Virgo trigger S200213t: Possible host galaxies
  36. LIGO/Virgo S200213t: NED Galaxies in the 90% Localization Volume
  37. LIGO/Virgo S200213t: 1 counterpart neutrino candidate from IceCube neutrino searches
  38. LIGO/Virgo S200213t: Identification of a GW compact binary merger candidate
  39. LIGO/Virgo S200213t: Global MASTER-Net observations report
  40. LIGO/Virgo S200208q: Updated Sky Localization
  41. LIGO/Virgo S200208q: No counterpart candidates in KAIT observations
  42. LIGO/Virgo S200208q: Not observable by CALET
  43. LIGO/Virgo S200208q: No counterpart candidates in Fermi-LAT observations
  44. LIGO/Virgo S200129m: Upper limits from Insight-HXMT/HE observations
  45. LIGO/Virgo S200208q: Coverage and upper limits from MAXI/GSC observations
  46. LIGO/Virgo S200208q: no counterpart candidates in the Swift/BAT observations
  47. LIGO/Virgo S200208q: Upper limits from Fermi-GBM Observations
  48. LIGO/Virgo S200208q : upper limits from AGILE/GRID observations
  49. LIGO/Virgo S200208q: upper limits from AGILE/MCAL observations
  50. LIGO/Virgo S200208q: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  51. LIGO/Virgo S200208q: Global MASTER-Net observations report
  52. LIGO/Virgo S200208q: No counterpart candidates in HAWC observations
  53. LIGO/Virgo S200208q : no neutrino counterpart candidate in ANTARES search
  54. LIGO/Virgo S200208q: Upper limits from IceCube neutrino searches
  55. LIGO/Virgo S200208q: Identification of a GW compact binary merger candidate
  56. LIGO/Virgo S200129m: Upper limits from Konus-Wind observations
  57. LIGO/Virgo S200128d: Upper limits from Konus-Wind observations
  58. AMON Coincidence Alert from the sub-threshold IceCube-HAWC search NuEm-200202A
  59. LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
  60. LIGO/Virgo S200128d : No significant candidates in FRAM - TAROT - GRANDMA observations
  61. LIGO/Virgo S200129m: Upper limits from CALET observations.
  62. LIGO/Virgo S200129m: no counterpart candidates in the Swift/BAT observations
  63. LIGO/Virgo S200129m: NED Galaxies in the 50% Localization Volume
  64. LIGO/Virgo S200129m: No counterpart candidates in Fermi-LAT observations
  65. LIGO/Virgo S200129m: Not observable by Fermi-GBM
  66. LIGO/Virgo S200128d: upper limits from AGILE/GRID observations
  67. LIGO/Virgo S200129m: Global MASTER-Net observations report
  68. LIGO/Virgo S200129m: upper limits from AGILE/GRID observations
  69. LIGO/Virgo S200129m: upper limits from AGILE/MCAL observations
  70. LIGO/Virgo S200129m: Coverage and upper limits from MAXI/GSC observations
  71. LIGO/Virgo S200129m: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  72. LIGO/Virgo S200129m: Upper limits from IceCube neutrino searches
  73. LIGO/Virgo S200129m: Identification of a GW compact binary merger candidate
  74. LIGO/Virgo S200128d: No counterpart candidates in Fermi-LAT observations
  75. LIGO/Virgo S200128d: Upper limits from CALET observations
  76. LIGO/Virgo S200128d: No counterpart candidates in KAIT observations
  77. LIGO/Virgo S200128d: no counterpart candidates in the Swift/BAT observations
  78. Fermi-LAT ANTARES 200127.79 coincidence: MASTER alert observation and presence of young pulsar close to error-box
  79. LIGO/Virgo S200128d: Upper limits from Fermi-GBM Observations
  80. LIGO/Virgo S200128d : no neutrino counterpart candidate in ANTARES search
  81. LIGO/Virgo S200128d: Coverage and upper limits from MAXI/GSC observations
  82. LIGO/Virgo S200128d: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  83. LIGO/Virgo S200128d: No counterpart candidates in HAWC observations
  84. LIGO/Virgo S200128d: Identification of a GW compact binary merger candidate
  85. LIGO/Virgo S200128d: Upper limits from IceCube neutrino searches
  86. LIGO/Virgo S200128d: Global MASTER-Net observations report
  87. LIGO/Virgo S200114f : No significant candidates in TAROT - FRAM - GRANDMA observations
  88. LIGO/Virgo S191222n: AstroSat CZTI upper limits
  89. LIGO/Virgo S200112r: AstroSat CZTI upper limits
  90. LIGO/Virgo S200114f: AstroSat CZTI upper limits
  91. LIGO/Virgo S200115j: Zwicky Transient Facility search for optical counterparts to Swift X-ray sources
  92. LIGO/Virgo S200115j: Further Swift-XRT sources
  93. LIGO/Virgo S200115j: Upper limits from Konus-Wind observations
  94. LIGO/Virgo S200114f: Upper limits from Konus-Wind observations
  95. LIGO/Virgo S200112r: Upper limits from Konus-Wind observations
  96. LIGO/VIRGO S200115j: No obvious candidates from Pan-STARRS2 observations
  97. LIGO/Virgo S200105ae: Upper limits from Konus-Wind observations
  98. LIGO/Virgo S191222n: Upper limits from Konus-Wind observations
  99. LIGO/Virgo S191216ap: Upper limits from Konus-Wind observations
  100. LIGO/Virgo S191215w: Upper limits from Konus-Wind observations

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