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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"

4256 results found.

  1. LIGO/Virgo S190910h: No significant candidates in TAROT-GRANDMA observations
  2. LIGO/Virgo S190915ak: Upper limits from IceCube neutrino searches
  3. LIGO/Virgo S190910d : No significant candidates in TAROT-GRANDMA observations
  4. LIGO/Virgo S190910h: No counterpart candidates in Fermi-LAT observations
  5. LIGO/Virgo S190910h: Upper limits from CALET observations.
  6. LIGO/Virgo S190910d and S190910h: No counterpart candidates in KAIT observations
  7. LIGO/Virgo S190910d: AstroSat CZTI upper limits
  8. LIGO/Virgo S190910h: no counterpart candidates in the Swift/BAT observations
  9. LIGO/Virgo S190910h: No counterpart candidates in AGILE-MCAL observations
  10. LIGO/Virgo S190910h : no neutrino counterpart candidate in ANTARES search
  11. LIGO/Virgo S190910h: Coverage and upper limits from MAXI/GSC observations
  12. LIGO/Virgo S190910h: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  13. LIGO/Virgo S190910h: Upper limits from IceCube neutrino searches
  14. LIGO/Virgo S190910h: Identification of a GW compact binary merger candidate
  15. Swift Trigger 924641 is an outburst from MAXI J1807+132
  16. LIGO/Virgo S190814bv: ATCA monitoring of ASKAP J005547-270433/AT2019osy
  17. LIGO/Virgo S190901ap: Gaia Photometric Alerts transient candidates
  18. LIGO/Virgo S190901ap : No significant candidates found in GRANDMA citizen science observations
  19. LIGO/Virgo S190814bv: GRAWITA VST-ESO PARANAL observations and independent transient candidates discovery.
  20. LIGO/Virgo S190901ap : No significant candidates in TAROT-GRANDMA
  21. LIGO/Virgo S190901ap: No counterpart candidates in KAIT observations
  22. IPN triangulation of GRB 190903A (short)
  23. LIGO/Virgo S190901ap : GRAWITA photometric observation of candidate ZTFabvizsw and GCN 25618 revision
  24. LIGO/Virgo S190901ap: no counterpart candidate in the SVOM/GWAC observations
  25. Chandra observations of GW170817 ~740-743 days since merger
  26. LIGO/Virgo S190814bv: ATCA observation of ASKAP J005547-270433/AT2019osy
  27. LIGO/Virgo S190901ap Global MASTER-Net observations report
  28. LIGO/Virgo S190901ap: Upper limits from IceCube neutrino searches
  29. LIGO/Virgo S190814bv : No significant candidates in TAROT-GRANDMA observations
  30. LIGO/Virgo S190828j : No significant candidates in TAROT-GRANDMA observations
  31. LIGO/Virgo S190828l: No significant candidates in TAROT-GRANDMA observations
  32. GRB 190829A: Liverpool Telescope observations
  33. GRB 190829A: AGILE-GRID upper limits
  34. GRB 190829A: AGILE ratemeters detection and MCAL upper limits
  35. GRB 190829A: Fermi GBM detection
  36. GRB 190829A: Fermi-LAT Upper Limits
  37. GRB 190829A:: Global MASTER-net optical clear and polarization observations scheduler and some spiculations
  38. LIGO/Virgo S190828l: No counterpart candidates in KAIT observations
  39. GRB 190829A:: MASTER-net bright and decay OT detection
  40. LIGO/Virgo S190829u Global MASTER-Net observations report
  41. GRB 190829A: Dabancheng-0.5m optical afterglow detection
  42. Fermi trigger No 588801358 Global MASTER-Net observations report
  43. GRB 190829A: Fermi GBM Final Real-time Localization
  44. GRB 190828B: VLT/X-shooter optical afterglow candidate
  45. LIGO/Virgo S190828j: No counterpart candidates in KAIT observations
  46. LIGO/Virgo S190828l: Upper limits from Fermi-GBM Observations
  47. LIGO/Virgo S190828l: Upper limits from IceCube neutrino searches
  48. LIGO/Virgo S190828j: Upper limits from IceCube neutrino searches
  49. GRB 190823A: MAXI/GSC detection
  50. Fermi trigger No 588185734 Global MASTER-Net observations report
  51. LIGO/Virgo S190814bv: No radio counterpart detected in ASKAP observations
  52. LIGO/Virgo S190822c: Upper limits from IceCube neutrino searches
  53. LIGO/Virgo S190814bv: No Optical Counterpart Candidates in Second-Epoch Lick/KAIT Observations
  54. GRB 190821A: Fermi GBM observation
  55. Fermi GBM-190816: Upper limits from IceCube neutrino searches
  56. LIGO/Virgo S190814bv: GRAWITA TNG NIR imaging of AT2019nqq and AT2019nqc
  57. GRB 190816A: Swift-XRT observations
  58. LIGO/Virgo S190814bv: Prioritization of Counterpart Candidates based on a Photometric Redshift Analysis by the DECam-GROWTH Team
  59. LIGO/Virgo S190814bv : No Counterpart Candidates in Continued Galaxy Targeted Search with Magellan
  60. LIGO/Virgo S190814bv: GROND imaging of candidate galaxies
  61. SUBJECT: LIGO/Virgo S190814bv: GRAWITA VST-ESO PARANAL observations
  62. S190814bv: MASTER analysis of DECam-GROWTH candidates
  63. LIGO/Virgo S190814bv : No Counterpart Candidates in Galaxy Targeted Search with Magellan
  64. GRB 190813A: Insight-HXMT/HE detection
  65. LIGO/Virgo S190814bv: No counterpart candidates in KAIT observations
  66. LIGO/Virgo S190814bv: no counterpart candidates in Swope imaging
  67. LIGO/Virgo S190814bv: KMTNet observation
  68. LIGO/Virgo S190814bv Global MASTER-Net optical observations
  69. LIGO/Virgo S190814bv : No counterpart candidate in TAROT-GRANDMA observations
  70. IPN triangulation of GRB 190813A (short)
  71. LIGO/Virgo S190814bv: Nordic Optical Telescope imaging of selected galaxies
  72. LIGO/Virgo S190814bv Global MASTER-Net observations report
  73. LIGO/Virgo S190814bv: Upper limits from IceCube neutrino searches
  74. Fermi trigger No 587392154 Global MASTER-Net observations report
  75. GRB 190813A: Fermi GBM Final Real-time Localization
  76. FRB 190806: MASTER optical observation
  77. LIGO/Virgo S190808ae: One Coincident Neutrino Candidate from IceCube Search
  78. LIGO/Virgo S190808ae Global MASTER-Net observations report
  79. IceCube-190730A: Upper limits from a search for additional neutrino events in IceCube
  80. IceCube-190730A - HAWC follow-up
  81. LIGO/Virgo S190728q: No counterpart candidates in H.E.S.S. observations
  82. LIGO/Virgo S190728q: ZTF Forced Photometry for PS1 and DECam-GROWTH optical candidates, and a note on DECam Photometry from GCN 25215
  83. LIGO/Virgo S190707q: AstroSat CZTI upper limits
  84. LIGO/Virgo S190718y: AstroSat CZTI upper limits
  85. LIGO/Virgo S190727h: AstroSat CZTI upper limits
  86. LIGO/Virgo S190720a: AstroSat CZTI upper limits
  87. LIGO/Virgo S190728q: MITSuME Okayama and Bisei Follow-Up of ZTF19abjethn (AT2019lvs)
  88. LIGO/Virgo S190728q: Optical transients from Pan-STARRS coverage during first 2 nights
  89. LIGO/Virgo S190728q: GRAWITA VST-ESO PARANAL observations
  90. LIGO/Virgo s190728q: ePESSTO+ NTT classification of AT2019lvt as a type-Ia SN
  91. LIGO/Virgo S190728q/IceCube neutrino candidate: No counterpart candidates in the Swift-XRT Observations
  92. Fermi Gamma-ray Burst Monitor trigger 190729668/586108936 is not a GRB
  93. S190728q: MASTER multiple previous outbursts detection of ZTF19abjethn=AT2019lvs
  94. LIGO/Virgo S190728q: No counterpart candidates in KAIT observations
  95. LIGO/Virgo S190728q: ZTF19abjethn TShAO and NUTTelA-TAO optical observations / classification
  96. LIGO/Virgo S190728q: Third update on neutrino search with IceCube
  97. LIGO/Virgo S190728q: Classification of AT2019lvs/ZTF19abjethn as a CV
  98. LIGO/Virgo S190728q: Second update on neutrino search with IceCube
  99. LIGO/Virgo S190728q: One neutrino candidate from IceCube search
  100. LIGO/Virgo S190728q: Upper limits from IceCube neutrino searches

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