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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"

3757 results found.

  1. GRB 190828B: optical upper limit from 0.5m Savelli Robotic Telescope
  2. LIGO/Virgo S190814bv: Swift observation of ASKAP J005547-270433/AT2019osy
  3. LIGO/Virgo S190828l: No counterpart candidates in Fermi-LAT observations
  4. LIGO/Virgo S190828l: No transient candidates in CALET observations
  5. LIGO/Virgo S190828j: No transient candidates in CALET observations
  6. GRB 190828B: Fermi GBM observation
  7. LIGO/Virgo S190828j: No counterpart candidates in KAIT observations
  8. LIGO/Virgo S190828j: No counterpart candidates in Fermi-LAT observations
  9. GRB 190828D: A long GRB detected by INTEGRAL
  10. Integral GRB190828.78 Global MASTER-Net observations report
  11. GRB 190828B: Dabancheng-0.5m optical upper limit
  12. GRB 190828C: BALROG localization (Fermi Trigger 588696271 / GRB 190828614)
  13. GRB 190828C: Fermi GBM Final Real-time Localization
  14. Swift GRB190828.54 Global MASTER-Net observations report
  15. GRB 190828B: Fermi GBM Final Real-time Localization
  16. LIGO/Virgo S190828l: Upper limits from AGILE-GRID observations
  17. LIGO/Virgo S190828l: Upper limits from IceCube neutrino searches
  18. LIGO/Virgo S190828j: Upper limits from IceCube neutrino searches
  19. LIGO/Virgo S190828l Global MASTER-Net observations report
  20. LIGO/Virgo S190828l: Coverage and upper limits from MAXI/GSC observations
  21. LIGO/Virgo S190828l: No counterpart candidates in AGILE-MCAL observations
  22. LIGO/Virgo S190828j: Coverage and upper limits from MAXI/GSC observations
  23. LIGO/Virgo S190828j : no neutrino counterpart candidate in ANTARES search
  24. LIGO/Virgo S190828l : no neutrino counterpart candidate in ANTARES search
  25. LIGO/Virgo S190828j: Upper limits from AGILE-GRID observations
  26. LIGO/Virgo S190828l: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  27. LIGO/Virgo S190828l: Identification of a GW compact binary merger candidate
  28. GRB 190828A: MAXI/GSC detection
  29. LIGO/Virgo S190828j: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  30. LIGO/Virgo S190828j: No counterpart candidates in AGILE-MCAL observations
  31. LIGO/Virgo S190828j: Identification of a GW compact binary merger candidate
  32. GRB 190824A, Swift-BAT refined analysis
  33. LIGO/Virgo S190814bv: LCO Photometry of DG19wxnjc/AT2019npv
  34. GRB 190823A: MAXI/GSC detection
  35. Fermi trigger No 588115134 Global MASTER-Net observations report
  36. Fermi GBM-190816: MASTER-Net optical observation report
  37. LIGO/Virgo S190814bv: No radio counterpart detected in ASKAP observations
  38. LIGO/Virgo S190814bv: No Optical Counterpart Candidates in Second-Epoch Lick/KAIT Observations
  39. LIGO/Virgo S190814bv: Further Pan-STARRS observations and transient sources
  40. LIGO/Virgo S190814bv: RATIR Optical observations of DECam transients
  41. LIGO/Virgo S190814bv : No Counterpart Candidates in Continued Galaxy Targeted Search with Magellan
  42. Baksan Neutrino Observatory Alert 190816.83 Global MASTER-Net observations report
  43. LIGO/Virgo S190814bv: GROND imaging of candidate galaxies
  44. LIGO/Virgo S190814bv: No counterpart candidates in KAIT observations
  45. LIGO/Virgo S190814bv: no counterpart candidates in Swope imaging
  46. LIGO/Virgo S190814bv: no counterpart candidates in Nickel/Direct imaging and non-detections of 2019nmd and 2019nme
  47. LIGO/Virgo S190814bv: no counterpart candidates in Keck I MOSFIRE imaging
  48. LIGO/Virgo S190814bv: no candidates from WHT imaging of candidate galaxies
  49. LIGO/Virgo S190814bv Global MASTER-Net observations report
  50. Fermi trigger No 587392154 Global MASTER-Net observations report
  51. IPN triangulation of GRB 190805B
  52. HAWC-190806A: Swift-XRT observations
  53. LIGO/Virgo S190728q: No counterpart candidates in H.E.S.S. observations
  54. LIGO/Virgo S190728q: ZTF Forced Photometry for PS1 and DECam-GROWTH optical candidates, and a note on DECam Photometry from GCN 25215
  55. IceCube-190730A: MASTER optical observation
  56. LIGO/Virgo S190728q: MITSuME Okayama and Bisei Follow-Up of ZTF19abjethn (AT2019lvs)
  57. LIGO/Virgo S190728q: Optical transients from Pan-STARRS coverage during first 2 nights
  58. LIGO/VIRGO S190728q: No candidate counterparts from ATLAS observations
  59. S190728q: MASTER multiple previous outbursts detection of ZTF19abjethn=AT2019lvs
  60. LIGO/Virgo S190728q: No transient candidates in CALET observations
  61. LIGO/Virgo S190728q: No counterpart candidates in KAIT observations
  62. LIGO/Virgo S190728q: ZTF19abjethn TShAO and NUTTelA-TAO optical observations / classification
  63. LIGO/Virgo S190728q: Third update on neutrino search with IceCube
  64. LIGO/Virgo S190728q: Classification of AT2019lvs/ZTF19abjethn as a CV
  65. LIGO/Virgo S190728q: LCO Follow-Up of ZTF19abjethn (AT2019lvs)
  66. LIGO/Virgo S190728q: No counterpart candidates in Fermi-LAT observations
  67. LIGO/Virgo S190728q: Second update on neutrino search with IceCube
  68. LIGO/Virgo S190728q: no counterpart candidates in AGILE-GRID observations
  69. LIGO/Virgo S190728q : no neutrino counterpart candidate in ANTARES search
  70. LIGO/Virgo S190728q: No counterpart candidates in AGILE-MCAL observations
  71. LIGO/Virgo S190728q: One neutrino candidate from IceCube search
  72. LIGO/Virgo S190728q: No counterpart candidates in INTEGRAL SPI-ACS prompt observation
  73. LIGO/Virgo S190728q: Coverage and upper limits from MAXI/GSC observations
  74. LIGO/Virgo S190728q: Identification of a GW compact binary merger candidate
  75. LIGO/Virgo S190728q: Upper limits from IceCube neutrino searches
  76. LIGO/Virgo S190727h: No transient candidates in CALET observations
  77. LIGO/Virgo S190728q Global MASTER-Net observations report
  78. Fermi trigger No 585988241 Global MASTER-Net observations report
  79. GRB 190728A: Fermi GBM Final Real-time Localization
  80. LIGO/Virgo S190727h: No counterpart candidates in KAIT observations
  81. LIGO/Virgo S190720a: Thacher Observatory follow-up observations
  82. Fermi trigger No 585621841 Global MASTER-Net observations report
  83. LIGO/Virgo S190720a: No counterpart candidates in KAIT observations
  84. LIGO/Virgo S190718y: No counterpart candidates in CNEOST
  85. LIGO/Virgo S190718y: No counterpart candidates in KAIT observations
  86. LIGO/Virgo S190718y: Upper limits from CALET observations
  87. Fermi trigger No 584977168 Global MASTER-Net observations report
  88. Fermi trigger No 584929684 Global MASTER-Net observations report
  89. IPN triangulation of GRB 190706C (long/very bright)
  90. LIGO/Virgo S190707q: Upper limits from CALET observations
  91. LIGO/Virgo S190706ai: No counterpart candidates in KAIT observations
  92. Fermi trigger No 584007338 Global MASTER-Net observations report
  93. Trigger 913042: Swift triggered on noise peak
  94. LIGO/Virgo S190630ag: no counterpart candidate in the SVOM/GWAC observations
  95. LIGO/Virgo S190701ah: KMTNet Observation
  96. LIGO/Virgo S190701ah: No transient candidates from CALET observations
  97. GRB 190627A: Koshka Zeiss-1000 optical counterpart observations
  98. GRB 190627A: GMG observation at the second epoch
  99. GRB 190627A: NUTTelA-TAO optical counterpart observations
  100. GRB 190628A: Fermi GBM Final Real-time Localization

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