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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. LIGO/Virgo G299232: Maidanak observations of optical transient SwiftJ014008.5+343403.6
  2. LIGO/Virgo G298389: Fermi GBM Flux Upper Limits
  3. LIGO/Virgo G299232: LOFAR follow-up
  4. Swift Trigger on continued activity of MAXI J1535-571
  5. GRB 170827A: LCO Observations
  6. GRB 170903A: Swift/UVOT Upper Limits
  7. GRB 170903A: UAFO /ISON optical upper limit
  8. LIGO/Virgo G298048: e-MERLIN upper limits on 5 GHz compact emission from SSS17a
  9. LIGO/Virgo G298048: ATCA monitoring of SSS17a in NGC 4993
  10. LIGO/Virgo G299232: RoboPol observations of MASTER OT J033744.97+723159.0
  11. GRB 170903A: MITSuME Okayama upper limits
  12. GRB 170903A: Swift-XRT refined Analysis
  13. GRB 170903A: Host galaxy redshift from OSIRIS/GTC
  14. LIGO/Virgo G298048: Chandra X-ray Update on GW170817
  15. GRB 170903A: Enhanced Swift-XRT position
  16. GRB 170903A: Swift-BAT refined analysis
  17. GRB 170903A: Nanshan optical upper limit
  18. GRB 170903A: Swift-XRT observations
  19. GRB 170903A: Swift detection of a burst
  20. Swift Triggers on MAXI J1535-571
  21. Swift Trigger 770431 (GRB 170902A) is a not a GRB
  22. GRB 170902A: Enhanced Swift-XRT position
  23. LIGO/Virgo G297595: DECam observations of BBH merger region of interest
  24. GRB 170902A: Swift detection of a burst or possible Galactic transient
  25. LIGO/Virgo G298048: Chandra monitoring of the X-ray emission from SSS17a
  26. LIGO/Virgo G298048: Continued X-ray monitoring and X-ray detection of GW170817 [erratum]]
  27. LIGO/Virgo G298048: AGILE-GRID analysis of data contemporary to X-ray emission from SSS17a in NGC4993
  28. LIGO/Virgo G298048
  29. LIGO/Virgo G299232/PGWB170825.55: MASTER archive images of the SIWFT/UVOT and MASTER OT J033744.97+723159.0 in NGC1343 galaxy before 25
  30. LIGO/Virgo G298048: Hubble Space Telescope observations
  31. LIGO/Virgo G299232: XSNAOC spectral observation of MASTER OTJ033744.97+723159.0
  32. LIGO/Virgo G298048: Possible Plateau in Ks band revealed by continued Gemini-South observations
  33. LIGO/Virgo G298048: Continued Gemini South observations
  34. GRB 170831A: Fermi GBM detection
  35. GRB 170830A: Fermi GBM observation
  36. Konus-Wind observation of GRB 170827B
  37. Konus-Wind observation of GRB 170826A
  38. GRB 170830A: Astrosat CZTI detection
  39. LIGO/Virgo G299232: GRAWITA Asiago optical observations
  40. LIGO/Virgo G299232: continued WHT observations of the field of SwiftJ014008.5+343403.6
  41. LIGO/Virgo G298936: PIRATE observations
  42. LIGO/Virgo G299232 ANTARES search (2)
  43. LIGO/Virgo G298048: GMRT Follow-up of SSS17a at 1.4 GHz
  44. Konus-Wind observation of GRB 170826B
  45. LIGO/Virgo G299232: GRAWITA Campo Imperatore optical observations
  46. LIGO/Virgo G298048: Discovery of X-ray emission from SSS17a in NGC4993
  47. GRB 170830A: iTelescope optical observations
  48. LIGO/Virgo G298048: European VLBI Network (EVN) upper limit on 5 GHz compact emission from SSS17a
  49. LIGO/Virgo G299232: SVOM/2.16-m Optical Telescope Observations of Swift UVOT Transient
  50. GRB 170830A: MAXI/GSC detection
  51. LIGO/Virgo G298048: OVRO 40m telescope follow-up
  52. LIGO/Virgo G299232: HAWC follow-up
  53. LIGO/Virgo G299232: Further Swift/UVOT Observations of Optical Transient SwiftJ014008.5+343403.6
  54. LIGO/Virgo G299232 : RATIR Optical and NIR Observations of Swift UVOT source
  55. LIGO/Virgo G299232: WHT non-detection u-band optical transient
  56. LIGO/Virgo G299232: Liverpool Telescope observations
  57. LIGO/Virgo G299232: observations of the optical Transient Discovered by Swift/UVOT
  58. IPN Triangulation of GRB 170826B
  59. LIGO/Virgo G299232: PIRATE observations of MASTER OT J033744.97+723159.0
  60. LIGO/Virgo G298936: Updated localization from parameter estimation on LIGO and Virgo data
  61. LIGO/Virgo G298048: ALMA upper limits on 98 GHz emission from SSS17a
  62. LIGO/Virgo G299232/PGWB170825.55: early MASTER observations of the Swift UVOT source position
  63. LIGO/Virgo G296853: PIRATE observations
  64. LIGO/Virgo G298048: ALMA observations
  65. LIGO/Virgo G298048: Konus-Wind observations
  66. LIGO/Virgo G299232: GRAWITA Asiago/Copernico Telescope observations
  67. LIGO/Virgo G298048: Zadko Telescope 7 day observations of the OT candidate SSS17a/DLT17ck
  68. GRB170827A: Further GROND follow-up observations
  69. LIGO/Virgo G299232: COATLI Observations of MASTER OT J033744.97+723159.0
  70. LIGO/Virgo G299232 : MAXI/GSC observations
  71. LIGO/Virgo G298048: Further ATCA follow-up of SSS17a in NGC 4993
  72. GRB 170826B: Insight-HXMT detection
  73. LIGO/Virgo G299232: Continued observation of the transient near NGC 1343
  74. LIGO/Virgo G299232: WHT spectrum of MASTER OT J033744.97+723159.0
  75. LIGO/Virgo G299232/PGWB170825.55: MASTER OT J033744.97+723159.0 inside 25m isophota of the NGC1343 galaxy is reddening
  76. IPN Triangulation of GRB 170827B (short)
  77. IPN Triangulation of GRB 170826A (short)
  78. LIGO/Virgo G299232: Optical Transient Discovery by Swift/UVOT
  79. LIGO/Virgo G298936: HAWC follow-up
  80. LIGO/Virgo G299232 TZAC/TAROT observations
  81. GRB 170827A: Swift-XRT refined Analysis
  82. GROND observations of GRB170827A
  83. GRB 170827A: ePESSTO NTT afterglow candidate
  84. GRB 170823A: TAROT Calern observatory optical observations
  85. LIGO/Virgo G299232: OVRO-LWA simultaneous low frequency radio observations of localization region
  86. LIGO/Virgo G299232: LOFAR follow-up
  87. GRB 170827A, Swift-BAT refined analysis
  88. LIGO/Virgo G299232: Transient near NGC 1343 has a somewhat blue r-i color
  89. GRB 170827A: Swift/UVOT Upper Limits
  90. GRB 170827A: REM optical/NIR observations
  91. LIGO/Virgo G299232/PGWB170825.55: MASTER OTJ033744.97+723159.0 off set from NGC1343 galaxy
  92. LIGO/Virgo G299232/PGWB170825.55: MASTER Global-Net OT inside NGC1343 discovery
  93. GRB 170827A: Swift detection of a burst
  94. GRB 170826B: Fermi GBM detection
  95. LIGO/Virgo G299232: CALET Observations
  96. GRB 170826A: Fermi GBM detection
  97. LIGO/Virgo G298936: Astrosat CZTI upper limits
  98. LIGO/Virgo G299232: XRT Rank 2 source is not real
  99. LIGO/Virgo G299232: Astrosat CZTI upper limits
  100. LIGO/VIRGO G299232: Fermi GBM Observations

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