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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"

44290 results found.

  1. GRB981220 VLBA observations
  2. GRB980425 Optical observations of exponential decline at late time
  3. GRB990321 REFINED IPN ANNULUS
  4. GRB990323 PRECISE IPN POSITION
  5. GRB990321 IPN TRIANGULATION
  6. GRB 990316 Optical Observations
  7. GRB 990316, Radio observations
  8. GRB 990316, Optical observations
  9. GRB990316, Optical observations
  10. GRB 990316 optical observations
  11. GRB990316: simultaneous optical observation
  12. GRB990316 - Optical null results
  13. ASM/IPN error box for GRB 990308 (BATSE #7457)
  14. GRB990308 not a new SGR
  15. GRB 990308a and GRB 990308b
  16. GRB990308 (Trig. 7457), optical observations
  17. GRB990308, Possible new SGR~0209+70
  18. GRB981220, IPN localization
  19. GRB 981220, radio observations
  20. GRB 990123, Field Photometry
  21. GRB 990217 Optical Observations
  22. GRB 990217, radio observations
  23. BATSE Resumes Normal Operations
  24. GRB990217: BeppoSAX/GRBM data
  25. Optical Observations of GRB990217
  26. GRB990123: Caltech STIS Photometry and Images
  27. GRB990123 observations
  28. GRB990217, WFC position
  29. GRB990123, Optical Observation
  30. GRB 990123: Discovery of the Probable Host Galaxy
  31. GRB 990123: Reduced HST Images
  32. For Immediate Posting to GCN - HST Data GRB 990123 Available
  33. GRB19990123 observations
  34. GRB 990123: BVRI standards in the field
  35. GRB 990123: Updated Keck Spectroscopy Results
  36. GRB981220, field photometry
  37. GRB 990123 NOT Spectrum Update
  38. GRB990123, Optical observation
  39. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  40. GRB 990123: Publicly available reduced HST images
  41. GRB990123, Upcoming HST Service Observations
  42. GRB990123, 15-GHz limits
  43. GRB 990123: New Constraints on Possible Foreground Galaxies
  44. GRB990123 Optical Observations
  45. GRB990123, Probability of gravitational lensing
  46. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  47. GRB 990123: Continued Radio Observations
  48. GRB990123, Preliminary Lens Search Results
  49. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  50. On the Lensing Interpretation of GRB 990123
  51. Search for Potential Images of GRB 990123
  52. Search for Potential Images of GRB 990123
  53. GRB990123, Optical BVRI Observations
  54. GRB 990123: near-infrared observations.
  55. GRB990123, OSSE observations
  56. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  57. GRB990123: NIR Observation
  58. GRB990123, ASCA X-ray observation of afterglow
  59. "GRB 990123: New BV Observations"
  60. GRB 990123 Optical Follow-Up
  61. GRB 990123; Addendum to GCN 223
  62. GRB 990123: BATSE Observations
  63. GRB 990123 Keck Spectrum update
  64. GRB990123 IPN annulus
  65. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  66. GRB990123 Optical Observations
  67. GRB 990123 Spectroscopic Redshifts
  68. GRB 990123: New Optical Observations, Decay Measure
  69. GRB 990123 Optical Follow-Up
  70. GRB 990123: Possible Gravitationally Lensed Burst?
  71. GRB990123, optical observation
  72. GRB 990123 optical observations
  73. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  74. GRB 990123 radio observations
  75. GRB 990123, new radio source
  76. GRB990123 optical observations
  77. GRB990123, Optical observation
  78. GRB 990123: Optical Decay Slope
  79. GRB 990123 r-band photometry
  80. GRB 990123 Optical Follow-up
  81. GRB990123, early optical counterpart detection
  82. GRB990123 Optical Observation
  83. GRB990123, BeppoSAX-NFI X-ray afterglow detection
  84. GRB990123, refined SAX-WFC position
  85. GRB 990123: Bright New Source, Possible Optical Transient
  86. GRB 990123, Radio observations
  87. GRB990123, BeppoSAX WFC detection and NFI planned follow-up
  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, Correction to GCN 179
  94. GRB981220, Optical Observations
  95. GRB 981220 Optical observations
  96. GRB 981226 Optical Observations
  97. GRB 980613: Spectroscopy of the host galaxy
  98. GRB981226, sub-millimeter observations
  99. GRB981220, sub-millimeter observations
  100. GRB 981220 and GRB 981226, optical observations

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