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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"

32498 results found.

  1. GRB000926 - Optical observations
  2. GRB 000926, Optical Decay
  3. GRB000911: VLT infrared observation
  4. GRB000926 - Optical observations
  5. GRB000926 - Optical observations
  6. GRB 000926: optical observations
  7. GRB 000926, Optical Observations
  8. GRB000926 - Optical observations
  9. GRB000911: optical VLT observations
  10. GRB000926 : increasing optical decay slope
  11. GRB000926 optical observations
  12. GRB000926 - Optical observations
  13. Re: GRB 000926, optical observation by Oksanen (vsnet-grb)
  14. J and K band observations of GRB 000926
  15. GRB000911 Optical Observations
  16. GRB 000926: Lightcurve Update and Predictions
  17. GRB 000926, optical observation by Oksanen (vsnet-grb)
  18. GRB000926: X-ray afterglow by BeppoSAX & plan of BSAX & Chandra obs.
  19. GRB000926: Optical observations
  20. GRB 000926: Preliminary R-band Lightcurve
  21. GRB 000926 HST/Chandra TOO Status
  22. Spectroscopic Redshift of GRB 000926
  23. GRB 000926, Optical Observation
  24. GRB000926, radio observations
  25. GRB 000926: Optical candidate
  26. Optical candidate for GRB000926
  27. IPN triangulation of GRB000926
  28. GRB 000911, BVRI field photometry
  29. GRB000911: Corrected coordinates
  30. GRB000911: Sub-millimeter observations
  31. GRB000911: Optical Transient
  32. GRB000911, Radio and Optical observations
  33. GRB000911, Radio observations
  34. GRB000911: Optical observations
  35. False GRB alarm from RXTE/ASM on 8 Sept 2000
  36. GRB 000830: Optical observations
  37. GRB000830: Optical observations
  38. GRB000830, TNG B-band observations
  39. GRB000830: Optical observations
  40. GRB000210, Optical observations
  41. Chandra Position of GRB000210
  42. GRB000830: Optical observations
  43. HST/STIS observations of the host galaxy of GRB 980329
  44. HST/STIS observations of the chaotic environment of GRB 980613
  45. GRB000812, TNG R-band observations
  46. GRB000801 & GRB000730, Gamma Ray Observations
  47. GRB000812, Radio observations
  48. GRB000801, VLT-Antu R-band observations
  49. GRB000301C, UBVI optical observations
  50. GRB000801, Radio Observations
  51. GRB 991208 Host Galaxy Imaging
  52. Updated IPN coordinates for GRB000801
  53. IPN localization of GRB000801
  54. IPN localization of GRB000730B
  55. GRB 990510: Possible detection of a host galaxy
  56. GRB 990510 Host Galaxy Discovery
  57. GRB 000727, optical observations
  58. GRB 990705, HST/STIS observations of the host galaxy
  59. GRB 990712: Late time HST/STIS Observations
  60. GRB 991216, HST/STIS observations
  61. GRB000620, Radio Observations
  62. GRB981226, HST/STIS observations of the host galaxy
  63. GRB000630, optical observations
  64. GRB 000630: Detection of the Optical Afterglow
  65. GRB000630, Revised BVRI Field Photometry
  66. GRB000630, Optical Observations
  67. GRB000630, optical observations
  68. GRB000630, optical observations
  69. GRB000630, optical observations
  70. GRB000630, optical observations
  71. GRB000630: Optical observations
  72. GRB000630, Radio Observations
  73. possible optical counterpart of GRB 000630
  74. GRB 000623, optical observations
  75. GRB 000620, optical observations
  76. GRB000418, HST/STIS Observations
  77. GRB990123: Late-time HST/STIS observations of the host
  78. GRB 990506, HST/STIS Observations of the Host Galaxy
  79. GRB 000620: J-band observations
  80. GRB000620, optical observations
  81. GRB000615: H-band observations
  82. GRB990308, HST/STIS observations of the host galaxy
  83. GRB000620 - Optical observations
  84. GRB000620 Optical observations
  85. IPN annulus for GRB000620
  86. GRB000615, Radio observations
  87. GRB000607, optical observations
  88. GRB 000615: NIR further observations
  89. GRB990123, HST/STIS observations of the host galaxy
  90. GRB000616 optical observations
  91. GRB 000615, near-infrared observations
  92. GRB 990123: Late-time HST/STIS 50CCD observations of the host
  93. GRB000615, further R-band photometry
  94. GRB 000615: NIR observations
  95. GRB000615, R-band photometry
  96. GRB980425, HST/STIS observations of the host galaxy
  97. The Hosts of GRB 980703 and GRB 971214
  98. GRB 000301C: Further Late-Time HST/STIS observations
  99. GRB000528: follow-up X-ray measurements and update of IPN annulus
  100. Optical Follow-up of GRB000529 Error Box

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