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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').
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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"

3616 results found.

  1. LIGO/Virgo S200219ac: upper limits from AGILE/GRID observations
  2. LIGO/Virgo S200213t: Keck/LRIS spectroscopy of counterpart candidates from the Zwicky Transient Facility
  3. LIGO/Virgo S200219ac: upper limits from AGILE/MCAL observations
  4. LIGO/Virgo S200219ac : no neutrino counterpart candidate in ANTARES search
  5. LIGO/Virgo S200219ac: Upper limits from IceCube neutrino searches
  6. LIGO/Virgo S200219ac: No counterpart candidates in HAWC observations
  7. LIGO/Virgo S200219ac: Coverage and upper limits from MAXI/GSC observations
  8. LIGO/Virgo S200219ac: No counterpart candidates in INTEGRAL SPI-ACS and IBIS prompt observation
  9. LIGO/Virgo S200219ac: Identification of a GW compact binary merger candidate
  10. LIGO/Virgo S200219ac: Global MASTER-Net observations report
  11. LIGO/Virgo (S200213t/IceCube neutrino candidate: No counterpart candidates in the Swift-XRT Observations
  12. LIGO/Virgo S200213t: No EM counterparts found from continued GECKO observation of host galaxy candidates
  13. LIGO/Virgo S200213t: APO Upper Limits for ZTF20aanakes/AT2020cly
  14. LIGO/Virgo S200213t : No significant candidates in FRAM - OAJ - TAROT - GRANDMA observations
  15. LIGO/Virgo S200213t: AstroSat CZTI upper limits
  16. LIGO/Virgo S200213t: Updated Sky Localization
  17. LIGO/Virgo S200213t: Updated coverage and candidate list for the Zwicky Transient Facility
  18. LIGO/Virgo S200213t: CLU/NED Galaxies in the 4-Update Localization Volume
  19. LIGO/Virgo S200213t: Possible host galaxies in the bilby skymap
  20. LIGO/Virgo S200213t: Updated Sky Localization
  21. LIGO/Virgo S200213t: Pre-discovery detections of MASTER OT J044008.76-651302.3
  22. LIGO/Virgo S200213t: No transient candidates in CALET observations
  23. LIGO/Virgo S200213t: Lulin Follow-Up Observations
  24. GRB 200215A: Nanshan/NEXT optical upper limit
  25. LIGO/Virgo S200213t: MASTER possible Kilonova candidate in PGC315337
  26. LIGO/Virgo S200213t: No neutrino candidates at Pierre Auger Observatory
  27. LIGO/Virgo S200213t: P200 Spectroscopy of ZTF20aanakcd/AT2020cmr
  28. LIGO/Virgo S200213t: DBSP spectroscopy of AT2020cjb/ZTF20aamvnth, AT2020cja/ZTF20aamvmzj, AT2020cjc/ZTF20aamvoeh
  29. LIGO/Virgo S200114f: Gemini Spectra of AT 2020vu, AT 2020vw, AT 2020vy, and AT 2020vz
  30. LIGO/Virgo S200213t: MASTER OT detection in PGC673735
  31. LIGO/Virgo S200213t: Upper limits from Insight-HXMT/HE observations
  32. LIGO/Virgo S200213t: No counterpart candidates from Nanshan-0.6m observations
  33. LIGO/Virgo S200213t: No notable candidates in GOTO imaging
  34. LIGO/Virgo S200213t: One additional candidate from the Zwicky Transient Facility
  35. LIGO/Virgo S200213t: No Counterparts from GECKO observation of host galaxy candidates in GW-neutrino detection overlap area
  36. LIGO/Virgo S200213t: No candidates found in J-GEM follow-up observations
  37. LIGO/Virgo S200213t: More Candidates from the Zwicky Transient Facility
  38. LIGO/Virgo S200213t: No counterpart candidates in KAIT observations
  39. LIGO/Virgo S200213t: AT2020ciz/ZTF20aamvnat, AT2020cjb/ZTF20aamvnth and 2020cjf/ZTF20aamvodd 10.4m GTC spectroscopy
  40. LIGO/Virgo S200213t: No counterpart candidates in Fermi-LAT observations
  41. LIGO/Virgo S200213t: No Counterparts in DDOTI/OAN Optical Observations
  42. LIGO/Virgo S200213t: AT2020ciy/ZTF20aamvqxl, AT2020cjg/ZTF20aamvoxx and AT2020cje/ZTF20aamvtip 10.4m GTC spectroscopy
  43. LIGO/Virgo S200213t: MANGROVE catalog galaxy ranking
  44. LIGO/Virgo S200213t: Swift/BAT in the South Atlantic Anomaly
  45. LIGO/Virgo S191213g: AT2019wxt Wendelstein optical observations
  46. LIGO/Virgo S200213t: not observable by Fermi-GBM
  47. LIGO/Virgo S200213t: upper limits from AGILE/GRID observations
  48. LIGO/Virgo S200208q : No significant candidates in TAROT - FRAM - GRANDMA observations
  49. LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
  50. LIGO/VIRGO S200213t: upper limits from AGILE/MCAL observations
  51. LIGO/Virgo S200213t: Candidates from the Zwicky Transient Facility
  52. LIGO/Virgo S200213t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  53. LIGO/Virgo S200213t : no neutrino counterpart candidate in ANTARES search
  54. LIGO/Virgo S200213t: Coverage and upper limits from MAXI/GSC observations
  55. LIGO/Virgo S200213t: Neutrino and galaxies cross-match
  56. LIGO/Virgo trigger S200213t: Possible host galaxies
  57. LIGO/Virgo S200213t: NED Galaxies in the 90% Localization Volume
  58. LIGO/Virgo S200213t: 1 counterpart neutrino candidate from IceCube neutrino searches
  59. LIGO/Virgo S200213t: Identification of a GW compact binary merger candidate
  60. LIGO/Virgo S200213t: Global MASTER-Net observations report
  61. LIGO/Virgo S200208q: Updated Sky Localization
  62. LIGO/Virgo S200208q: No counterpart candidates in KAIT observations
  63. LIGO/Virgo S200208q: Not observable by CALET
  64. LIGO/Virgo S200208q: No counterpart candidates in Fermi-LAT observations
  65. LIGO/Virgo S200129m: Upper limits from Insight-HXMT/HE observations
  66. LIGO/Virgo S200208q: Coverage and upper limits from MAXI/GSC observations
  67. LIGO/Virgo S200208q: no counterpart candidates in the Swift/BAT observations
  68. LIGO/Virgo S200208q: Upper limits from Fermi-GBM Observations
  69. LIGO/Virgo S200208q : upper limits from AGILE/GRID observations
  70. LIGO/Virgo S200208q: upper limits from AGILE/MCAL observations
  71. LIGO/Virgo S200208q: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  72. LIGO/Virgo S200208q: Global MASTER-Net observations report
  73. LIGO/Virgo S200208q: No counterpart candidates in HAWC observations
  74. LIGO/Virgo S200208q : no neutrino counterpart candidate in ANTARES search
  75. LIGO/Virgo S200208q: Upper limits from IceCube neutrino searches
  76. LIGO/Virgo S200208q: Identification of a GW compact binary merger candidate
  77. LIGO/Virgo S200129m: Upper limits from Konus-Wind observations
  78. LIGO/Virgo S200128d: Upper limits from Konus-Wind observations
  79. LIGO/Virgo S200128d: no counterpart candidate in SVOM/GWAC observations
  80. LIGO/Virgo S200128d : No significant candidates in FRAM - TAROT - GRANDMA observations
  81. LIGO/Virgo S200129m: Upper limits from CALET observations.
  82. LIGO/Virgo S200129m: no counterpart candidates in the Swift/BAT observations
  83. LIGO/Virgo S200129m: NED Galaxies in the 50% Localization Volume
  84. LIGO/Virgo S200129m: No counterpart candidates in Fermi-LAT observations
  85. LIGO/Virgo S200129m: Not observable by Fermi-GBM
  86. LIGO/Virgo S200128d: upper limits from AGILE/GRID observations
  87. LIGO/Virgo S200129m: Global MASTER-Net observations report
  88. LIGO/Virgo S200129m: upper limits from AGILE/GRID observations
  89. LIGO/Virgo S200129m: upper limits from AGILE/MCAL observations
  90. LIGO/Virgo S200129m: Coverage and upper limits from MAXI/GSC observations
  91. LIGO/Virgo S200129m: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  92. LIGO/Virgo S200129m: Upper limits from IceCube neutrino searches
  93. LIGO/Virgo S200129m: Identification of a GW compact binary merger candidate
  94. LIGO/Virgo S200128d: No counterpart candidates in Fermi-LAT observations
  95. LIGO/Virgo S200128d: Upper limits from CALET observations
  96. LIGO/Virgo S200128d: No counterpart candidates in KAIT observations
  97. LIGO/Virgo S200128d: no counterpart candidates in the Swift/BAT observations
  98. Fermi-LAT ANTARES 200127.79 coincidence: MASTER alert observation and presence of young pulsar close to error-box
  99. LIGO/Virgo S200128d: Upper limits from Fermi-GBM Observations
  100. LIGO/Virgo S200128d : no neutrino counterpart candidate in ANTARES search

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