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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"

36681 results found.

  1. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  2. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  3. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  4. radio observations of X-ray/GRB transient field
  5. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  6. Optical report on X-ray/GRB transient
  7. radio detection of X-ray/GRB transient
  8. BeppoSAX: A new fast X-ray transient
  9. GRB 990510: optical observations
  10. GRB990510: photometric and spectroscopic observations with the VLT
  11. GRB 990510: optical linear polarization
  12. GRB 990510: optical observations
  13. GRB990510, VI observations
  14. GRB 990506 R band observations
  15. GRB990510: X-ray afterglow
  16. GRB 990510: optical observation
  17. VLT spectrum of GRB990510
  18. GRB 990510: Broad Band Break
  19. GRB 990510: BATSE Observations
  20. GRB 990510 Optical Observations
  21. GRB 990510, BVI photometry
  22. GRB 990510 optical observations
  23. GRB 990510: BeppoSAX/GRBM observations
  24. GRB990510 optical observations
  25. GRB 990510 optical observations
  26. GRB 990510 optical observations
  27. Galactic extinction towards GRB 990510
  28. GRB 990510 optical observations
  29. IPN localization of GRB990510
  30. GRB 990506 Radio Observations
  31. GRB 990123, optical monitoring
  32. GRB 990506: BATSE Observations
  33. GRB 990506, optical observations
  34. GRB 990510: Final BeppoSAX-WFC Coordinates
  35. GRB 990506, Optical Observations
  36. GRB 990506 optical observations
  37. GRB 990506 optical observations
  38. GRB 990506, optical observations
  39. GRB990506 observation plan
  40. Refined IPN error box for GRB990506
  41. GRB 990506: Limits on the possible optical transient
  42. GRB 990506, armchair astronomy
  43. GRB 990506, optical observations from +1 to +3 hours
  44. GRB 990506, optical observations
  45. GRB990506 observation plan
  46. New IPN/RXTE error box for GRB990506
  47. IPN localization for GRB990506
  48. GRB 970228: Redshift and properties of the host galaxy
  49. IPN localization of GRB990427
  50. GRB981220 VLBA observations
  51. GRB990321 REFINED IPN ANNULUS
  52. GRB990323 PRECISE IPN POSITION
  53. GRB990321 IPN TRIANGULATION
  54. GRB 990316 Optical Observations
  55. GRB 990316, Radio observations
  56. GRB 990316, Optical observations
  57. GRB990316, Optical observations
  58. GRB 990316 optical observations
  59. GRB990316: simultaneous optical observation
  60. ASM/IPN error box for GRB 990308 (BATSE #7457)
  61. GRB990308 not a new SGR
  62. GRB 990308a and GRB 990308b
  63. GRB990308 (Trig. 7457), optical observations
  64. GRB981220, IPN localization
  65. GRB 981220, radio observations
  66. GRB 990123, Field Photometry
  67. GRB 990217 Optical Observations
  68. GRB 990217, radio observations
  69. Optical Observations of GRB990217
  70. GRB990123: Caltech STIS Photometry and Images
  71. GRB990123 observations
  72. GRB990123, Optical Observation
  73. GRB 990123: Discovery of the Probable Host Galaxy
  74. GRB 990123: Reduced HST Images
  75. For Immediate Posting to GCN - HST Data GRB 990123 Available
  76. GRB19990123 observations
  77. GRB 990123: BVRI standards in the field
  78. GRB 990123: Updated Keck Spectroscopy Results
  79. GRB981220, field photometry
  80. GRB 990123 NOT Spectrum Update
  81. GRB990123, Optical observation
  82. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  83. GRB 990123: Publicly available reduced HST images
  84. GRB990123, Upcoming HST Service Observations
  85. GRB 990123: New Constraints on Possible Foreground Galaxies
  86. GRB990123 Optical Observations
  87. GRB990123, Probability of gravitational lensing
  88. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  89. GRB 990123: Continued Radio Observations
  90. GRB990123, Preliminary Lens Search Results
  91. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  92. On the Lensing Interpretation of GRB 990123
  93. Search for Potential Images of GRB 990123
  94. Search for Potential Images of GRB 990123
  95. GRB990123, Optical BVRI Observations
  96. GRB 990123: near-infrared observations.
  97. GRB990123, OSSE observations
  98. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  99. "GRB 990123: New BV Observations"
  100. GRB 990123 Optical Follow-Up

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