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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"

35946 results found.

  1. GRB 990506 optical observations
  2. GRB 990506 optical observations
  3. GRB 990506, optical observations
  4. GRB990506 observation plan
  5. Refined IPN error box for GRB990506
  6. GRB 990506: Limits on the possible optical transient
  7. GRB 990506, armchair astronomy
  8. GRB 990506, optical observations from +1 to +3 hours
  9. GRB 990506, optical observations
  10. GRB990506 observation plan
  11. New IPN/RXTE error box for GRB990506
  12. IPN localization for GRB990506
  13. GRB 970228: Redshift and properties of the host galaxy
  14. IPN localization of GRB990427
  15. GRB981220 VLBA observations
  16. GRB990321 REFINED IPN ANNULUS
  17. GRB990323 PRECISE IPN POSITION
  18. GRB990321 IPN TRIANGULATION
  19. GRB 990316 Optical Observations
  20. GRB 990316, Radio observations
  21. GRB 990316, Optical observations
  22. GRB990316, Optical observations
  23. GRB 990316 optical observations
  24. GRB990316: simultaneous optical observation
  25. ASM/IPN error box for GRB 990308 (BATSE #7457)
  26. GRB990308 not a new SGR
  27. GRB 990308a and GRB 990308b
  28. GRB990308 (Trig. 7457), optical observations
  29. GRB981220, IPN localization
  30. GRB 981220, radio observations
  31. GRB 990123, Field Photometry
  32. GRB 990217 Optical Observations
  33. GRB 990217, radio observations
  34. Optical Observations of GRB990217
  35. GRB990123: Caltech STIS Photometry and Images
  36. GRB990123 observations
  37. GRB990123, Optical Observation
  38. GRB 990123: Discovery of the Probable Host Galaxy
  39. GRB 990123: Reduced HST Images
  40. For Immediate Posting to GCN - HST Data GRB 990123 Available
  41. GRB19990123 observations
  42. GRB 990123: BVRI standards in the field
  43. GRB 990123: Updated Keck Spectroscopy Results
  44. GRB981220, field photometry
  45. GRB 990123 NOT Spectrum Update
  46. GRB990123, Optical observation
  47. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  48. GRB 990123: Publicly available reduced HST images
  49. GRB990123, Upcoming HST Service Observations
  50. GRB 990123: New Constraints on Possible Foreground Galaxies
  51. GRB990123 Optical Observations
  52. GRB990123, Probability of gravitational lensing
  53. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  54. GRB 990123: Continued Radio Observations
  55. GRB990123, Preliminary Lens Search Results
  56. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  57. On the Lensing Interpretation of GRB 990123
  58. Search for Potential Images of GRB 990123
  59. Search for Potential Images of GRB 990123
  60. GRB990123, Optical BVRI Observations
  61. GRB 990123: near-infrared observations.
  62. GRB990123, OSSE observations
  63. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  64. "GRB 990123: New BV Observations"
  65. GRB 990123 Optical Follow-Up
  66. GRB 990123; Addendum to GCN 223
  67. GRB 990123: BATSE Observations
  68. GRB 990123 Keck Spectrum update
  69. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  70. GRB990123 Optical Observations
  71. GRB 990123 Spectroscopic Redshifts
  72. GRB 990123: New Optical Observations, Decay Measure
  73. GRB 990123 Optical Follow-Up
  74. GRB 990123: Possible Gravitationally Lensed Burst?
  75. GRB 990123 optical observations
  76. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  77. GRB 990123 radio observations
  78. GRB 990123, new radio source
  79. GRB990123, Optical observation
  80. GRB 990123: Optical Decay Slope
  81. GRB 990123 r-band photometry
  82. GRB 990123 Optical Follow-up
  83. GRB990123, early optical counterpart detection
  84. GRB990123 Optical Observation
  85. GRB 990123: Bright New Source, Possible Optical Transient
  86. GRB 990123, Radio observations
  87. SN 1999E & GRB 980919
  88. Possible identification of SN1999E with GRB980910
  89. Optical Observations of GRB 981220
  90. GRB 981226: radio variable
  91. GRB981220
  92. GRB981220, Optical Observations
  93. GRB 981220 Optical observations
  94. GRB 981226 Optical Observations
  95. GRB 980613: Spectroscopy of the host galaxy
  96. GRB981226, sub-millimeter observations
  97. GRB981220, sub-millimeter observations
  98. GRB 981220 and GRB 981226, optical observations
  99. GRB 981226 radio observations
  100. GRB 981226

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