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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"

35951 results found.

  1. GRB000926 K'-band Observation
  2. GRB000926 : increasing optical decay slope
  3. GRB000926 optical observations
  4. GRB000926 - Optical observations
  5. Re: GRB 000926, optical observation by Oksanen (vsnet-grb)
  6. J and K band observations of GRB 000926
  7. GRB 000926: Lightcurve Update and Predictions
  8. GRB 000926, optical observation by Oksanen (vsnet-grb)
  9. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  10. CONCAM crude optical limits before and after GRB000926
  11. GRB 000926: Preliminary R-band Lightcurve
  12. GRB 000926 HST/Chandra TOO Status
  13. Spectroscopic Redshift of GRB 000926
  14. GRB 000926, Optical Observation
  15. GRB 000926: Optical candidate
  16. Optical candidate for GRB000926
  17. IPN triangulation of GRB000926
  18. GRB 000911, BVRI field photometry
  19. GRB000911: Sub-millimeter observations
  20. IPN triangulation of GRB000925
  21. IPN triangulation of GRB000911
  22. IPN triangulation of GRB000910
  23. False GRB alarm from RXTE/ASM on 8 Sept 2000
  24. GRB 000830: Optical observations
  25. GRB000830: Optical observations
  26. GRB000830, TNG B-band observations
  27. GRB000830, BVRI field photometry
  28. GRB000830: Optical observations
  29. GRB000210, Optical observations
  30. Chandra Position of GRB000210
  31. "Snapshot" afterglow IDs and GRB 000830
  32. IPN triangulation of GRB000830
  33. HST/STIS observations of the host galaxy of GRB 980329
  34. HST/STIS observations of the chaotic environment of GRB 980613
  35. IPN localization of GRB000820
  36. GRB000801 & GRB000730, Gamma Ray Observations
  37. GRB000730, Gamma Ray Observations
  38. GRB000812, Radio observations
  39. IPN localization of GRB000812
  40. IPN localization of GRB000811
  41. GRB000801, Gamma Ray Observations
  42. GRB000801, VLT-Antu R-band observations
  43. GRB 991208 Host Galaxy Imaging
  44. Updated IPN coordinates for GRB000801
  45. IPN localization of GRB000801
  46. IPN localization of GRB000730B
  47. IPN localization of GRB000730B
  48. IPN localization of GRB000730
  49. GRB 990510: Possible detection of a host galaxy
  50. GRB 990510 Host Galaxy Discovery
  51. GRB 000727, optical observations
  52. IPN localization of GRB000727
  53. GRB 990705, HST/STIS observations of the host galaxy
  54. GRB 990712: Late time HST/STIS Observations
  55. GRB 991216, HST/STIS observations
  56. GRB981226, HST/STIS observations of the host galaxy
  57. GRB 000630: Detection of the Optical Afterglow
  58. GRB000630, Revised BVRI Field Photometry
  59. GRB000630, Optical Observations
  60. GRB000630, optical observations
  61. GRB000630, BVRI Field Photometry
  62. GRB000630, optical observations
  63. GRB000630: Optical observations
  64. possible optical counterpart of GRB 000630
  65. IPN triangulation of GRB000630
  66. GRB 000623, optical observations
  67. GRB 000620, optical observations
  68. GRB000418, HST/STIS Observations
  69. GRB990123: Late-time HST/STIS observations of the host
  70. GRB 990506, HST/STIS Observations of the Host Galaxy
  71. GRB000623
  72. GRB 000620: J-band observations
  73. GRB990308, HST/STIS observations of the host galaxy
  74. IPN annulus for GRB000620
  75. GRB000615, Radio observations
  76. GRB000607, optical observations
  77. GRB 000615: NIR further observations
  78. BeppoSAX ALERT: GRB000620
  79. GRB000620: BeppoSAX Alert
  80. GRB990123, HST/STIS observations of the host galaxy
  81. GRB 000615, near-infrared observations
  82. GRB 990123: Late-time HST/STIS 50CCD observations of the host
  83. GRB000616 [IPN Position]
  84. GRB000615B [IPN Position]
  85. GRB000615, further R-band photometry
  86. GRB 000615: NIR observations
  87. GRB000615: BeppoSAX NFI follow-up preliminary analysis
  88. GRB000615, R-band photometry
  89. GRB980425, HST/STIS observations of the host galaxy
  90. GRB000615: BeppoSAX GRB Alert
  91. The Hosts of GRB 980703 and GRB 971214
  92. GRB 000301C: Further Late-Time HST/STIS observations
  93. GRB000528: follow-up X-ray measurements and update of IPN annulus
  94. GRB980519, HST/STIS observations of the host galaxy
  95. GRB000607, Radio Observations
  96. GRB000604 - Optical observations
  97. GRB000607, A SHORT, HARD BURST
  98. GRB000604, optical observations
  99. GRB000528, optical observations at ESO
  100. GRB 000604 optical observations

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