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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"

36947 results found.

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

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