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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"

31738 results found.

  1. GRB000620, Radio Observations
  2. GRB981226, HST/STIS observations of the host galaxy
  3. GRB000630, optical observations
  4. GRB 000630: Detection of the Optical Afterglow
  5. GRB000630, Revised BVRI Field Photometry
  6. GRB000630, Optical Observations
  7. GRB000630, optical observations
  8. GRB000630, optical observations
  9. GRB000630, optical observations
  10. GRB000630, optical observations
  11. GRB000630: Optical observations
  12. GRB000630, Radio Observations
  13. possible optical counterpart of GRB 000630
  14. GRB 000623, optical observations
  15. GRB 000620, optical observations
  16. GRB000418, HST/STIS Observations
  17. GRB990123: Late-time HST/STIS observations of the host
  18. GRB 990506, HST/STIS Observations of the Host Galaxy
  19. GRB 000620: J-band observations
  20. GRB000620, optical observations
  21. GRB000615: H-band observations
  22. GRB990308, HST/STIS observations of the host galaxy
  23. GRB000620 - Optical observations
  24. GRB000620 Optical observations
  25. IPN annulus for GRB000620
  26. GRB000615, Radio observations
  27. GRB000607, optical observations
  28. GRB 000615: NIR further observations
  29. GRB990123, HST/STIS observations of the host galaxy
  30. GRB000616 optical observations
  31. GRB 000615, near-infrared observations
  32. GRB 990123: Late-time HST/STIS 50CCD observations of the host
  33. GRB000615, further R-band photometry
  34. GRB 000615: NIR observations
  35. GRB000615, R-band photometry
  36. GRB980425, HST/STIS observations of the host galaxy
  37. The Hosts of GRB 980703 and GRB 971214
  38. GRB 000301C: Further Late-Time HST/STIS observations
  39. GRB000528: follow-up X-ray measurements and update of IPN annulus
  40. Optical Follow-up of GRB000529 Error Box
  41. GRB000607, Radio Observations
  42. GRB000604 optical non-detection
  43. GRB000604 - Optical observations
  44. GRB000604, optical observations
  45. GRB000528, optical observations at ESO
  46. GRB 000604 optical observations
  47. GRB 000418: Detection of the Host Galaxy
  48. GRB000604, optical observations, comparison with DPOSS
  49. GRB000528, Radio Observations
  50. X-ray Afterglow of GRB 000529
  51. GRB000528: BeppoSAX NFI follow-up preliminary analysis
  52. IPN localization and time history of GRB000528
  53. New IPN localization of GRB000529
  54. GRB000519: Optical observations
  55. IPN localization of GRB000529
  56. GRB 000528 - WFC measurements
  57. IPN triangulation of GRB000519
  58. Re: GRB000508B : Optical observations
  59. GRB 000418, Optical observation
  60. GRB000508B, optical photometry
  61. Possible GRB-related phenomenon
  62. GRB 000424 Optical Observations
  63. The redshift of GRB 000418
  64. GRB000424, optical observations
  65. GRB 000429, optical observation
  66. GRB000418, Radio detection
  67. GRB000418, K'-band photometry
  68. GRB 000418, Optical Observation
  69. GRB 000418, optical observation
  70. GRB000424 Optical Observations
  71. GRB 000418, Optical Observation
  72. GRB000424, optical observations
  73. GRB000424, optical observations
  74. GRB 000424, Optical Observations
  75. GRB 000418, Optical Observation
  76. GRB000418, near-infrared observations
  77. BeppoSAX GRB000424
  78. Correction to IPN error box for GRB000419
  79. BATSE observations of FXT/GRB 000416 = 1SAXJ1715.0-7134
  80. RE: Budget cuts in BeppoSAX operations: impact on GRB observation
  81. X-ray burst or X-ray rich GRB 000416 observed by BeppoSAX
  82. GRB 000408, optical observations
  83. Refined IPN error box for GRB000408
  84. GRB000301c results
  85. GRB000408: Optical CCD Observations from MIRO
  86. GRB000408, lotis optical observations
  87. GRB 000301C: Late-Time HST/STIS CCD Imaging of the field
  88. GRB000326 Optical Observations
  89. GRB000301C - Addendum to GCN 623
  90. GRB000326, Further VLA observations
  91. GRB 000323, optical observations
  92. GRB 000326: Optical Observations
  93. GRB000326, Radio observations
  94. GRB 000307 optical observations
  95. Single error box for GRB000315
  96. GRB000313, Radio observations
  97. GRB000301C - B and R photometry
  98. GRB 000307, Optical Observations
  99. GRB 000301C: Optical Spectrum and Redshift
  100. GRB 000301C: Optical Spectrum and Redshift

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