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Old Q0957+561 data & software: 

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► HST-STIS Spectra

► Simple FORTRAN programs to apply the d² test (accurate and robust time delay measurements)

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Spectra of Q0957+561A and Q0957+561B were obtained in 1999 April 15 and 2000 June 2-3, respectively, with the Space Telescope Imaging Spectrograph (STIS) on board the HST. The spectra of each image cover a wide range of wavelengths, from the near-infrared (NIR) to the ultraviolet (UV), since the G230L, G430L and G750L gratings were used in the experiment. The central wavelengths of these gratings are 0.24 mm (G230L), 0.43 mm (G430L) and 0.77 mm (G750L). A 52 ´ 0.2 arcsec² slit was also used in each observation. The final data (flux vs. wavelength) are calibrated with the last version of the CALSTIS pipeline software (v2.15c, 29 January 2004), so the corrections for time-dependent sensitivity of the MAMA detectors (which is relevant for the G230L observations) as well as for charge-transfer efficiency of the CCD detector (relevant for the G430L and G750L observations) are incorporated. The relevant data files are:

Q0957+561A/G230L                            Q0957+561B/G230L

Q0957+561A/G430L                            Q0957+561B/G430L

Q0957+561A/G750L                            Q0957+561B/G750L  .

CONTINUUM FLUX RATIOS (averaging over independent intervals of 100 Å; results from this FORTRAN file)

Central wavelength        Flux ratio (B/A)                        Error in B/A

          (Å)

     2400.000                                         1.158076                                        2.6371948E-02
     2590.000                                         1.178547                                        2.5041372E-02
     2700.000                                         1.190996                                        1.6915184E-02
     2810.000                                         1.219100                                        3.0338937E-02
     3070.000                                         1.145900                                        3.7491947E-02
     3500.000                                         1.142315                                        1.5858240E-02
     3900.000                                         1.116825                                        1.0021350E-02
     4100.000                                         1.133345                                        1.0237115E-02
     4210.000                                         1.105921                                        1.0108775E-02
     4320.000                                         1.113857                                        9.0285232E-03
     4430.000                                         1.101657                                        1.1300926E-02
     4800.000                                         1.100102                                        1.1657312E-02
     4910.000                                         1.088247                                        9.1866311E-03
     5020.000                                         1.079346                                        1.0172051E-02
     5130.000                                         1.093521                                        1.0703269E-02
     5240.000                                         1.098544                                        1.2220921E-02
     5350.000                                         1.089939                                        8.7200934E-03
     6000.000                                         1.047736                                        1.2290484E-02
     6500.000                                         1.034119                                        1.1102841E-02
     6610.000                                         1.007791                                        1.2159928E-02
     7300.000                                         1.025052                                        1.3210475E-02
     7410.000                                         1.041935                                        1.3225742E-02
     7520.000                                         1.034279                                        1.5076437E-02
     7630.000                                         1.018898                                        1.4216989E-02
     7740.000                                         1.000759                                        1.9093486E-02
     7850.000                                         1.018336                                        2.0242479E-02
     8500.000                                         1.040726                                        2.7930584E-02
     8610.000                                         1.013656                                        2.7357228E-02
     8720.000                                         1.030178                                        2.3813087E-02
     9000.000                                         1.000969                                        3.3085965E-02
     9300.000                                         1.070461                                        4.1031498E-02
     9410.000                                         0.9979929                                      4.9538895E-02

 EMISSION LINE FLUX RATIOS

Emission line                   Flux ratio (B/A)  

   MgII (l2798)                                0.64 ± 0.04

   CIII (l1909)                                  0.78 ± 0.03

   CIV (l1549)                                  0.77 ± 0.02

   NV (l1240)                                   0.67 ± 0.07

   Lya (l1216)                                0.87 ± 0.03

The paper on the analysis and interpretation of the spectra is available HERE.