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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"

35155 results found.

  1. Galactic extinction towards GRB 990510
  2. GRB 990510 optical observations
  3. IPN localization of GRB990510
  4. GRB 990506 Radio Observations
  5. GRB 990123, optical monitoring
  6. GRB 990506: BATSE Observations
  7. GRB 990506, optical observations
  8. GRB 990510: Final BeppoSAX-WFC Coordinates
  9. GRB 990506, Optical Observations
  10. GRB 990506 optical observations
  11. GRB 990506 optical observations
  12. GRB 990506, optical observations
  13. GRB990506 observation plan
  14. Refined IPN error box for GRB990506
  15. GRB 990506: Limits on the possible optical transient
  16. GRB 990506, armchair astronomy
  17. GRB 990506, optical observations from +1 to +3 hours
  18. GRB 990506, optical observations
  19. GRB990506 observation plan
  20. New IPN/RXTE error box for GRB990506
  21. IPN localization for GRB990506
  22. GRB 970228: Redshift and properties of the host galaxy
  23. IPN localization of GRB990427
  24. GRB981220 VLBA observations
  25. GRB990321 REFINED IPN ANNULUS
  26. GRB990323 PRECISE IPN POSITION
  27. GRB990321 IPN TRIANGULATION
  28. GRB 990316 Optical Observations
  29. GRB 990316, Radio observations
  30. GRB 990316, Optical observations
  31. GRB990316, Optical observations
  32. GRB 990316 optical observations
  33. GRB990316: simultaneous optical observation
  34. ASM/IPN error box for GRB 990308 (BATSE #7457)
  35. GRB990308 not a new SGR
  36. GRB 990308a and GRB 990308b
  37. GRB990308 (Trig. 7457), optical observations
  38. GRB981220, IPN localization
  39. GRB 981220, radio observations
  40. GRB 990123, Field Photometry
  41. GRB 990217 Optical Observations
  42. GRB 990217, radio observations
  43. Optical Observations of GRB990217
  44. GRB990123: Caltech STIS Photometry and Images
  45. GRB990123 observations
  46. GRB990123, Optical Observation
  47. GRB 990123: Discovery of the Probable Host Galaxy
  48. GRB 990123: Reduced HST Images
  49. For Immediate Posting to GCN - HST Data GRB 990123 Available
  50. GRB19990123 observations
  51. GRB 990123: BVRI standards in the field
  52. GRB 990123: Updated Keck Spectroscopy Results
  53. GRB981220, field photometry
  54. GRB 990123 NOT Spectrum Update
  55. GRB990123, Optical observation
  56. GRB990123, is the "radio flare" due to an inhomogeneous medium?
  57. GRB 990123: Publicly available reduced HST images
  58. GRB990123, Upcoming HST Service Observations
  59. GRB 990123: New Constraints on Possible Foreground Galaxies
  60. GRB990123 Optical Observations
  61. GRB990123, Probability of gravitational lensing
  62. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  63. GRB 990123: Continued Radio Observations
  64. GRB990123, Preliminary Lens Search Results
  65. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  66. On the Lensing Interpretation of GRB 990123
  67. Search for Potential Images of GRB 990123
  68. Search for Potential Images of GRB 990123
  69. GRB990123, Optical BVRI Observations
  70. GRB 990123: near-infrared observations.
  71. GRB990123, OSSE observations
  72. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  73. "GRB 990123: New BV Observations"
  74. GRB 990123 Optical Follow-Up
  75. GRB 990123; Addendum to GCN 223
  76. GRB 990123: BATSE Observations
  77. GRB 990123 Keck Spectrum update
  78. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  79. GRB990123 Optical Observations
  80. GRB 990123 Spectroscopic Redshifts
  81. GRB 990123: New Optical Observations, Decay Measure
  82. GRB 990123 Optical Follow-Up
  83. GRB 990123: Possible Gravitationally Lensed Burst?
  84. GRB 990123 optical observations
  85. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  86. GRB 990123 radio observations
  87. GRB 990123, new radio source
  88. GRB990123, Optical observation
  89. GRB 990123: Optical Decay Slope
  90. GRB 990123 r-band photometry
  91. GRB 990123 Optical Follow-up
  92. GRB990123, early optical counterpart detection
  93. GRB990123 Optical Observation
  94. GRB 990123: Bright New Source, Possible Optical Transient
  95. GRB 990123, Radio observations
  96. SN 1999E & GRB 980919
  97. Possible identification of SN1999E with GRB980910
  98. Optical Observations of GRB 981220
  99. GRB 981226: radio variable
  100. GRB981220

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