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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').
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"
  1. GRB 200216A: Fermi GBM detection
  2. LIGO/Virgo S200213t: AstroSat CZTI upper limits
  3. GRB 200216B: z-band limit from NOT
  4. GRB 200216B: Fermi GBM observation
  5. GRB 200216B: Swift/UVOT Upper Limits
  6. GRB 200216A: Swift/BAT detection and arcminute localization from GUANO
  7. GRB 200216B: Enhanced Swift-XRT position
  8. GRB 200215A: RATIR Optical Observations
  9. GRB 200216B: Nanshan/NEXT early optical upper limit and possible host galaxy
  10. GRB 200216B: GMG upper limit
  11. GRB 200216B: Swift detection of a burst
  12. GRB 200216B: Fermi GBM Final Real-time Localization
  13. Swift GRB200216.56: Global MASTER-Net observations report
  14. GRB 200215A: UKIRT H-band observations
  15. GRB 200215A: Swift-BAT refined analysis
  16. GRB 200216A: Fermi GBM Final Real-time Localization
  17. LIGO/Virgo S200213t: Updated Sky Localization
  18. LIGO/Virgo S200213t: Updated coverage and candidate list for the Zwicky Transient Facility
  19. LIGO/Virgo S200213t: CLU/NED Galaxies in the 4-Update Localization Volume
  20. LIGO/Virgo S200213t: Possible host galaxies in the bilby skymap
  21. LIGO/Virgo S200213t: Updated Sky Localization
  22. GRB 200215A: Swift-XRT refined Analysis
  23. GRB 200215A: Swift/UVOT Upper Limits
  24. GRB 200215A: Enhanced Swift-XRT position
  25. GRB 200215A: Optical observations form Calar Alto 2.2m
  26. GRB 200215A: Fermi GBM detection
  27. GRB 200215A: Liverpool Telescope upper limits
  28. LIGO/Virgo S200213t: Pre-discovery detections of MASTER OT J044008.76-651302.3
  29. LIGO/Virgo S200213t: No transient candidates in CALET observations
  30. GRB 200215A Possible host galaxy in PanSTARRS
  31. LIGO/Virgo S200213t: Lulin Follow-Up Observations
  32. GRB 200215A: Nanshan/NEXT optical upper limit
  33. Swift GRB200215.61: Global MASTER-Net observations report
  34. GRB 200215A: Swift detection of a burst
  35. GRB 200215A: Fermi GBM Final Real-time Localization
  36. LIGO/Virgo S200213t: MASTER possible Kilonova candidate in PGC315337
  37. LIGO/Virgo S200213t: No neutrino candidates at Pierre Auger Observatory
  38. LIGO/Virgo S200213t: P200 Spectroscopy of ZTF20aanakcd/AT2020cmr
  39. LIGO/Virgo S200213t: DBSP spectroscopy of AT2020cjb/ZTF20aamvnth, AT2020cja/ZTF20aamvmzj, AT2020cjc/ZTF20aamvoeh
  40. LIGO/Virgo S200114f: Gemini Spectra of AT 2020vu, AT 2020vw, AT 2020vy, and AT 2020vz
  41. LIGO/Virgo S200213t: MASTER OT detection in PGC673735
  42. LIGO/Virgo S200213t: Upper limits from Insight-HXMT/HE observations
  43. LIGO/Virgo S200213t: No counterpart candidates from Nanshan-0.6m observations
  44. LIGO/Virgo S200213t: No notable candidates in GOTO imaging
  45. LIGO/Virgo S200213t: One additional candidate from the Zwicky Transient Facility
  46. LIGO/Virgo S200213t: No Counterparts from GECKO observation of host galaxy candidates in GW-neutrino detection overlap area
  47. LIGO/Virgo S200213t: No candidates found in J-GEM follow-up observations
  48. LIGO/Virgo S200213t: More Candidates from the Zwicky Transient Facility
  49. LIGO/Virgo S200213t: No counterpart candidates in KAIT observations
  50. LIGO/Virgo S200213t: AT2020ciz/ZTF20aamvnat, AT2020cjb/ZTF20aamvnth and 2020cjf/ZTF20aamvodd 10.4m GTC spectroscopy
  51. LIGO/Virgo S200213t: No counterpart candidates in Fermi-LAT observations
  52. LIGO/Virgo S200213t: No Counterparts in DDOTI/OAN Optical Observations
  53. LIGO/Virgo S200213t: AT2020ciy/ZTF20aamvqxl, AT2020cjg/ZTF20aamvoxx and AT2020cje/ZTF20aamvtip 10.4m GTC spectroscopy
  54. LIGO/Virgo S200213t: MANGROVE catalog galaxy ranking
  55. LIGO/Virgo S200213t: Swift/BAT in the South Atlantic Anomaly
  56. LIGO/Virgo S191213g: AT2019wxt Wendelstein optical observations
  57. LIGO/Virgo S200213t: not observable by Fermi-GBM
  58. LIGO/Virgo S200213t: upper limits from AGILE/GRID observations
  59. LIGO/Virgo S200208q : No significant candidates in TAROT - FRAM - GRANDMA observations
  60. LIGO/Virgo S200208q: no counterpart candidate in SVOM/C-GFT observations
  61. LIGO/VIRGO S200213t: upper limits from AGILE/MCAL observations
  62. LIGO/Virgo S200213t: Candidates from the Zwicky Transient Facility
  63. LIGO/Virgo S200213t: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  64. LIGO/Virgo S200213t : no neutrino counterpart candidate in ANTARES search
  65. LIGO/Virgo S200213t: Coverage and upper limits from MAXI/GSC observations
  66. LIGO/Virgo S200213t: Neutrino and galaxies cross-match
  67. GRB 2002011A: AstroSat CZTI detection
  68. LIGO/Virgo trigger S200213t: Possible host galaxies
  69. LIGO/Virgo S200213t: NED Galaxies in the 90% Localization Volume
  70. LIGO/Virgo S200213t: 1 counterpart neutrino candidate from IceCube neutrino searches
  71. LIGO/Virgo S200213t: Identification of a GW compact binary merger candidate
  72. LIGO/Virgo S200213t: Global MASTER-Net observations report
  73. GRB 200212A: Fermi GBM Final Localization Correction
  74. ZTF20aajnksq: Upper limits from Konus-Wind observations
  75. Fermi trigger No 603197394: Global MASTER-Net observations report
  76. GRB 200212A: Fermi GBM Final Real-time Localization
  77. LIGO/Virgo S200208q: Updated Sky Localization
  78. GRB 200131A: Tautenburg observations
  79. Konus-Wind observation of GRB 200205B
  80. LIGO/Virgo S200208q: No counterpart candidates in KAIT observations
  81. GRB 200211A: BALROG localization (Fermi Trigger 603098793 / GRB 200211310)
  82. GRB 200211A: Fermi GBM Final Real-time Localization
  83. LIGO/Virgo S200208q: Not observable by CALET
  84. GRB 200207A: AstroSat CZTI detection
  85. LIGO/Virgo S200208q: No counterpart candidates in Fermi-LAT observations
  86. GRB 200205B: Chilescope optical observations
  87. LIGO/Virgo S200129m: Upper limits from Insight-HXMT/HE observations
  88. GRB 200120A: Fermi GBM observation
  89. LIGO/Virgo S200208q: Coverage and upper limits from MAXI/GSC observations
  90. LIGO/Virgo S200208q: no counterpart candidates in the Swift/BAT observations
  91. LIGO/Virgo S200208q: Upper limits from Fermi-GBM Observations
  92. LIGO/Virgo S200208q : upper limits from AGILE/GRID observations
  93. LIGO/Virgo S200208q: upper limits from AGILE/MCAL observations
  94. LIGO/Virgo S200208q: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  95. LIGO/Virgo S200208q: Global MASTER-Net observations report
  96. LIGO/Virgo S200208q: No counterpart candidates in HAWC observations
  97. LIGO/Virgo S200208q : no neutrino counterpart candidate in ANTARES search
  98. LIGO/Virgo S200208q: Upper limits from IceCube neutrino searches
  99. LIGO/Virgo S200208q: Identification of a GW compact binary merger candidate
  100. Fermi trigger No 602817262: Global MASTER-Net observations report

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