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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"

35952 results found.

  1. GRB 000926, Optical Observations
  2. GRB000926 K'-band Observation
  3. GRB000926 : increasing optical decay slope
  4. GRB000926 optical observations
  5. GRB000926 - Optical observations
  6. Re: GRB 000926, optical observation by Oksanen (vsnet-grb)
  7. J and K band observations of GRB 000926
  8. GRB 000926: Lightcurve Update and Predictions
  9. GRB 000926, optical observation by Oksanen (vsnet-grb)
  10. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  11. CONCAM crude optical limits before and after GRB000926
  12. GRB 000926: Preliminary R-band Lightcurve
  13. GRB 000926 HST/Chandra TOO Status
  14. Spectroscopic Redshift of GRB 000926
  15. GRB 000926, Optical Observation
  16. GRB 000926: Optical candidate
  17. Optical candidate for GRB000926
  18. IPN triangulation of GRB000926
  19. GRB 000911, BVRI field photometry
  20. GRB000911: Sub-millimeter observations
  21. IPN triangulation of GRB000925
  22. IPN triangulation of GRB000911
  23. IPN triangulation of GRB000910
  24. False GRB alarm from RXTE/ASM on 8 Sept 2000
  25. GRB 000830: Optical observations
  26. GRB000830: Optical observations
  27. GRB000830, TNG B-band observations
  28. GRB000830, BVRI field photometry
  29. GRB000830: Optical observations
  30. GRB000210, Optical observations
  31. Chandra Position of GRB000210
  32. "Snapshot" afterglow IDs and GRB 000830
  33. IPN triangulation of GRB000830
  34. HST/STIS observations of the host galaxy of GRB 980329
  35. HST/STIS observations of the chaotic environment of GRB 980613
  36. IPN localization of GRB000820
  37. GRB000801 & GRB000730, Gamma Ray Observations
  38. GRB000730, Gamma Ray Observations
  39. GRB000812, Radio observations
  40. IPN localization of GRB000812
  41. IPN localization of GRB000811
  42. GRB000801, Gamma Ray Observations
  43. GRB000801, VLT-Antu R-band observations
  44. GRB 991208 Host Galaxy Imaging
  45. Updated IPN coordinates for GRB000801
  46. IPN localization of GRB000801
  47. IPN localization of GRB000730B
  48. IPN localization of GRB000730B
  49. IPN localization of GRB000730
  50. GRB 990510: Possible detection of a host galaxy
  51. GRB 990510 Host Galaxy Discovery
  52. GRB 000727, optical observations
  53. IPN localization of GRB000727
  54. GRB 990705, HST/STIS observations of the host galaxy
  55. GRB 990712: Late time HST/STIS Observations
  56. GRB 991216, HST/STIS observations
  57. GRB981226, HST/STIS observations of the host galaxy
  58. GRB 000630: Detection of the Optical Afterglow
  59. GRB000630, Revised BVRI Field Photometry
  60. GRB000630, Optical Observations
  61. GRB000630, optical observations
  62. GRB000630, BVRI Field Photometry
  63. GRB000630, optical observations
  64. GRB000630: Optical observations
  65. possible optical counterpart of GRB 000630
  66. IPN triangulation of GRB000630
  67. GRB 000623, optical observations
  68. GRB 000620, optical observations
  69. GRB000418, HST/STIS Observations
  70. GRB990123: Late-time HST/STIS observations of the host
  71. GRB 990506, HST/STIS Observations of the Host Galaxy
  72. GRB000623
  73. GRB 000620: J-band observations
  74. GRB990308, HST/STIS observations of the host galaxy
  75. IPN annulus for GRB000620
  76. GRB000615, Radio observations
  77. GRB000607, optical observations
  78. GRB 000615: NIR further observations
  79. BeppoSAX ALERT: GRB000620
  80. GRB000620: BeppoSAX Alert
  81. GRB990123, HST/STIS observations of the host galaxy
  82. GRB 000615, near-infrared observations
  83. GRB 990123: Late-time HST/STIS 50CCD observations of the host
  84. GRB000616 [IPN Position]
  85. GRB000615B [IPN Position]
  86. GRB000615, further R-band photometry
  87. GRB 000615: NIR observations
  88. GRB000615: BeppoSAX NFI follow-up preliminary analysis
  89. GRB000615, R-band photometry
  90. GRB980425, HST/STIS observations of the host galaxy
  91. GRB000615: BeppoSAX GRB Alert
  92. The Hosts of GRB 980703 and GRB 971214
  93. GRB 000301C: Further Late-Time HST/STIS observations
  94. GRB000528: follow-up X-ray measurements and update of IPN annulus
  95. GRB980519, HST/STIS observations of the host galaxy
  96. GRB000607, Radio Observations
  97. GRB000604 - Optical observations
  98. GRB000607, A SHORT, HARD BURST
  99. GRB000604, optical observations
  100. GRB000528, optical observations at ESO

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