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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"

31728 results found.

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

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