8126( 4) - 05/11/99 10:13 - [ 1] PROPOSAL FOR HUBBLE SPACE TELESCOPE OBSERVATIONS ST ScI Use Only ID: 8126 Version: 4 Check-in Date: 11-May-1999 10:11:56 1.Proposal Title: STIS OBSERVATIONS OF QSO PAIRS ------------------------------------------------------------------------------------ 2. Proposal For 3. Cycle GO 8 ------------------------------------------------------------------------------------ 4. Investigators Contact? PI: Patrick Petitjean Institut D'Astrophysique de Paris CoI: Dr. Alain Smette NASA-Goddard Space Flight Center N CoI: Dr. Jean Surdej Institut d'Astrophysique, Liege N CoI: Dr. Jan Muecket Astrophysikalisches Institut Potsdam N CoI: Prof. Stefano Cristiani European Southern Observatory N CoI: Dr. Marc Remy Institut d'Astrophysique, Liege N ------------------------------------------------------------------------------------ 5. Abstract We propose to obtain STIS ultraviolet spectra of four QSO pairs with similar common redshift ranges (z ~ 0.7--1) and projected linear separations gradually increasing from ~0.5 to sim1 h^-1_100 Mpc in order (i) to probe the extension and structure of gaseous complexes giving rise to the formation of LyAlpha absorption lines at intermediate redshift (z ~ 0.9) (ii) to investigate the transversal proximity effect of the foreground quasar along the line of sight to the background quasar; (iii) study the environment in which QSOs reside and in particular the presence of gas around the foreground quasar. Given the brightness of the QSOs to be observed (B ~eq 17.9 -- 18.4) and the spectral range of interest (1900 Angstrom <= Lambda <= 3100 Angstrom), HST + STIS provides us with the unique existing instrumental capability to perform the proposed observations. ------------------------------------------------------------------------------------ 8126( 4) - 05/11/99 10:13 - [ 2] Observations Description ------------------------ We intend to use the STIS G230L grating associated with the NUV-MAMA. Although the spectral resolution is slighly smaller compared to the G230LB, the sensitivity over the wavelength range of interest is better. Indeed, in 7500s on a B = 18 quasar, we can achieve S/N > 20-25 over the wavelength range 2000- 3000 Angstrom. Our observing time request is based on this assumption. The 3Sigma rest equivalent width limit will be therefore smaller than 0.24 Angstrom over this wavelength range and will decrease down to 0.10 Angstrom in the wing of the LyAlpha emission line. Given these assumptions, we can estimate the number of lines expected along each line of sight (see following Table, last columns). These numbers are similar to what we have observed toward Q1026-- 0025A, B and should altogether decrease the uncertainties in the determination of the radius (or of the correlation length) by a factor of three (see Fig. 4 in D'Odorico et al. 1998, astro- ph/9806204). The minimum co mm on redshift interval, Delta z(min), is calculated assuming that there is a LLS at the emission redshift of the quasar. It must be noted that the occurence of such systems is rare (see Jannuzi et al. 1998, astro-ph/9805148). Moreover we have checked on the spectra available in the literature that there is no associated MgII systems. For Q0035-3520 and Q0037-3545 we have two low- resolution high S/N ratio spectra showing that the equivalent width limit is smaller than 0.5 Angstrom. The maximum common redshift range, Delta z(max), is the range over which the equivalent width limit will be wr < 0.24 Angstrom, if there is no LLS. The number density of lines is taken from Jannuzi et al. (1998) to be No(w_ r > 0.24 Angstrom)=33.6+/-2.9.------------------------------------------- ---------------------------------- Name z V Separation Deltaz Nb of lines (a) (mag) (arcs)(h-1kpc) min max min max -------------------------------------- --------------------------------------- Q0037-3545 1.095 18.4 110 458 0.71 0.26 0.26 8.9 8.9 Q0037-3544 0.836 18.1 PB161 1.559 17.9 170 708 0.96 0.20 0.47 6.7 15.7 Q1320+4755B 1.111 18.3 PB5893 1.588 18.1 198 825 0.80 0.10 0.39 3.4 13.1 UM230 1.040 18.1 Q0035-3518 1.199 18.0 229 954 0.99 0.31 0.55 10.4 18.6 Q0035- 3520 1.519 18.4---------------------------------------------------------------- ------------- (a) along each line of sight in the common redshift range Given the integration time, the time for target acquisition and overheads, we find that a total of 26 orbits is necessary to achieve the observations of these four pairs of quasars. Real Time Justification ----------------------- Calibration Justification ------------------------- Additional Comments ------------------- ------------------------------------------------------------------------------------ 8126( 4) - 05/11/99 10:13 - [ 3] Data Distribution Paper Products: NO Media: ELECTRONIC Blocking Factor: 10 Ship To: PI_Address Ship Via: Email: ------------------------------------------------------------------------------------ 8126( 4) - 05/11/99 10:13 - [ 4] TARGET LIST a) Fixed Targets ------------------------------------------------------------------------------------------------------------------------------------ Tar| Target | Target | Target |Coord | Radial | Flux data No | Name | Description | Position |Eqnx | Vel. | ------------------------------------------------------------------------------------------------------------------------------------ 1 LBQS0019- GALAXY, QSO, LYMAN RA=0H 21M 51.8S +/- 0.1", DEC=- J2000 Z = V = 18.1+/-0.15 0145A ALPHA CLOUD 1D 28' 34.11" +/- 1", PLATE- 1.588 ID=00WS 2 LBQS0019- GALAXY, QSO, LYMAN RA=0H 22M 4.89S +/- 0.1", DEC=- J2000 Z = 1.04 V = 18.1+/-0.15 0145B ALPHA CLOUD 1D 28' 48.07" +/- 1.", PLATE- ID=00WS 3 Q0035-3518 GALAXY, QSO, LYMAN RA=0H 38M 5.54S +/- 0.1", DEC=- J2000 Z = V = 17.6+/-0.15 ALPHA CLOUD 35D 1' 40.34" +/- 1.", PLATE- 1.199 ID=02S6 4 Q0035-3520 GALAXY, QSO, LYMAN RA=0H 38M 17.45S +/- 0.1", DEC=- J2000 Z = V = 18.34+/-0.15 ALPHA CLOUD 35D 4' 5.36" +/- 1.", PLATE- 1.519 ID=02S6 5 Q0037-3545 GALAXY, QSO, LYMAN RA=0H 39M 37.28S +/- 0.1", DEC=- J2000 Z = V = 18.48+/-0.15 ALPHA CLOUD 35D 29' 17.10" +/- 1.", PLATE- 1.519 ID=024K 6 Q0037-3544 GALAXY, QSO, LYMAN RA=0H 39M 42.57S +/- 0.1", DEC=- J2000 Z = V = 18.1+/-0.15 ALPHA CLOUD 35D 28' 0.48" +/- 1.", PLATE- 0.836 ID=024K 7 PC1320+4755A GALAXY, QSO, LYMAN RA=13H 22M 39.33S +/- 0.1", J2000 Z = V = 17.94+/-0.15 ALPHA CLOUD DEC=47D 39' 27.97" +/- 1.", 1.559 PLATE-ID=00XQ 8 PC1320+4755B GALAXY, QSO, LYMAN RA=13H 22M 50.72S +/- 0.1", J2000 Z = V = 18.33+/-0.15 ALPHA CLOUD DEC=47D 39' 36.55" +/- 1.", 1.111 PLATE-ID=00XQ 8126( 4) - 05/11/99 10:13 - [ 5] Visit: 01 Visit Priority: Visit Requirements: GROUP 01 - 02 WITHIN 30D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 LBQS0019-01 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 10 S ONBOARD ACQ FOR 20 45A CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 LBQS0019-01 STIS/C ACQ/PEA 52X0.2 MIRROR 1 10 S ONBOARD ACQ FOR 30, 35, 45A CD K 40, 45, 50 ------------------------------------------------------------------------------------------------------------------------------------ 30 LBQS0019-01 STIS/N ACCUM 52X0.2 G230L 2376 1 2100 S EXPAND 45A UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 35 WAVE STIS/N ACCUM 52X0.2 G230L 2376 1 DEF UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 40 LBQS0019-01 STIS/N ACCUM 52X0.2 G230L 2376 1 2900 S EXPAND POS TARG 0, 5 45A UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 45 WAVE STIS/N ACCUM 52X0.2 G230L 2376 1 DEF UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 50 LBQS0019-01 STIS/N ACCUM 52X0.2 G230L 2376 1 2900 S EXPAND POS TARG 0,-5 45A UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8126( 4) - 05/11/99 10:13 - [ 6] Visit: 02 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 LBQS0019-01 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 10 S ONBOARD ACQ FOR 20 45B CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 LBQS0019-01 STIS/C ACQ/PEA 52X0.2 MIRROR 1 10 S ONBOARD ACQ FOR 30, 35, 45B CD K 40, 45, 50 ------------------------------------------------------------------------------------------------------------------------------------ 30 LBQS0019-01 STIS/N ACCUM 52X0.2 G230L 2376 1 2100 S EXPAND 45B UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 35 WAVE STIS/N ACCUM 52X0.2 G230L 2376 1 DEF UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 40 LBQS0019-01 STIS/N ACCUM 52X0.2 G230L 2376 1 2900 S EXPAND POS TARG 0, 5 45B UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 45 WAVE STIS/N ACCUM 52X0.2 G230L 2376 1 DEF UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 50 LBQS0019-01 STIS/N ACCUM 52X0.2 G230L 2376 1 2900 S EXPAND POS TARG 0,-5 45B UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8126( 4) - 05/11/99 10:13 - [ 7] Visit: 03 Visit Priority: Visit Requirements: GROUP 03 - 04 WITHIN 30D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 Q0035-3518 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 9 S ONBOARD ACQ FOR 20 CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 Q0035-3518 STIS/C ACQ/PEA 52X0.2 MIRROR 1 9 S ONBOARD ACQ FOR 30, 35, CD K 40, 45, 50 ------------------------------------------------------------------------------------------------------------------------------------ 30 Q0035-3518 STIS/N ACCUM 52X0.2 G230L 2376 1 2100 S EXPAND UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 35 WAVE STIS/N ACCUM 52X0.2 G230L 2376 1 DEF UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 40 Q0035-3518 STIS/N ACCUM 52X0.2 G230L 2376 1 2900 S EXPAND POS TARG 0, 5 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 45 WAVE STIS/N ACCUM 52X0.2 G230L 2376 1 DEF UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 50 Q0035-3518 STIS/N ACCUM 52X0.2 G230L 2376 1 2900 S EXPAND POS TARG 0,-5 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8126( 4) - 05/11/99 10:13 - [ 8] Visit: 04 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 Q0035-3520 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 13 S ONBOARD ACQ FOR 20 CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 Q0035-3520 STIS/C ACQ/PEA 52X0.2 MIRROR 1 13 S ONBOARD ACQ FOR 30, 35, CD K 40, 45, 50, 55, 60 ------------------------------------------------------------------------------------------------------------------------------------ 30 Q0035-3520 STIS/N ACCUM 52X0.2 G230L 2376 1 2100 S EXPAND UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 35 WAVE STIS/N ACCUM 52X0.2 G230L 2376 1 DEF UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 40 Q0035-3520 STIS/N ACCUM 52X0.2 G230L 2376 1 2900 S EXPAND POS TARG 0, 5 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 45 WAVE STIS/N ACCUM 52X0.2 G230L 2376 1 DEF UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 50 Q0035-3520 STIS/N ACCUM 52X0.2 G230L 2376 1 2900 S EXPAND POS TARG 0,-5 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 55 WAVE STIS/N ACCUM 52X0.2 G230L 2376 1 DEF UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 60 Q0035-3520 STIS/N ACCUM 52X0.2 G230L 2376 1 2900 S EXPAND POS TARG 0,-10 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8126( 4) - 05/11/99 10:13 - [ 9] Visit: 05 Visit Priority: Visit Requirements: GROUP 05 - 06 WITHIN 30D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 Q0037-3545 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 14 S ONBOARD ACQ FOR 20 CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 Q0037-3545 STIS/C ACQ/PEA 52X0.2 MIRROR 1 14 S ONBOARD ACQ FOR 30, 35, CD K 40, 45, 50, 55, 60 ------------------------------------------------------------------------------------------------------------------------------------ 30 Q0037-3545 STIS/N ACCUM 52X0.2 G230L 2376 1 2100 S EXPAND UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 35 WAVE STIS/N ACCUM 52X0.2 G230L 2376 1 DEF UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 40 Q0037-3545 STIS/N ACCUM 52X0.2 G230L 2376 1 2900 S EXPAND POS TARG 0, 5 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 45 WAVE STIS/N ACCUM 52X0.2 G230L 2376 1 DEF UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 50 Q0037-3545 STIS/N ACCUM 52X0.2 G230L 2376 1 2900 S EXPAND POS TARG 0,-5 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 55 WAVE STIS/N ACCUM 52X0.2 G230L 2376 1 DEF UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 60 Q0037-3545 STIS/N ACCUM 52X0.2 G230L 2376 1 2900 S EXPAND POS TARG 0,-10 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8126( 4) - 05/11/99 10:13 - [ 10] Visit: 06 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 Q0037-3544 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 9 S ONBOARD ACQ FOR 20 CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 Q0037-3544 STIS/C ACQ/PEA 52X0.2 MIRROR 1 9 S ONBOARD ACQ FOR 30, 35, CD K 40, 45, 50 ------------------------------------------------------------------------------------------------------------------------------------ 30 Q0037-3544 STIS/N ACCUM 52X0.2 G230L 2376 1 2100 S EXPAND UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 35 WAVE STIS/N ACCUM 52X0.2 G230L 2376 1 DEF UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 40 Q0037-3544 STIS/N ACCUM 52X0.2 G230L 2376 1 2900 S EXPAND POS TARG 0, 5 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 45 WAVE STIS/N ACCUM 52X0.2 G230L 2376 1 DEF UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 50 Q0037-3544 STIS/N ACCUM 52X0.2 G230L 2376 1 2900 S EXPAND POS TARG 0,-5 UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8126( 4) - 05/11/99 10:13 - [ 11] Visit: 07 Visit Priority: Visit Requirements: GROUP 07 - 08 WITHIN 30D On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 PC1320+4755 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 10 S ONBOARD ACQ FOR 20 A CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 PC1320+4755 STIS/C ACQ/PEA 52X0.2 MIRROR 1 10 S ONBOARD ACQ FOR 30, 35, A CD K 40, 45, 50 ------------------------------------------------------------------------------------------------------------------------------------ 30 PC1320+4755 STIS/N ACCUM 52X0.2 G230L 2376 1 2100 S EXPAND A UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 35 WAVE STIS/N ACCUM 52X0.2 G230L 2376 1 DEF UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 40 PC1320+4755 STIS/N ACCUM 52X0.2 G230L 2376 1 2900 S EXPAND POS TARG 0, 5 A UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 45 WAVE STIS/N ACCUM 52X0.2 G230L 2376 1 DEF UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 50 PC1320+4755 STIS/N ACCUM 52X0.2 G230L 2376 1 2900 S EXPAND POS TARG 0,-5 A UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8126( 4) - 05/11/99 10:13 - [ 12] Visit: 08 Visit Priority: Visit Requirements: On Hold Comments: Additional Comments: Exposures ------------------------------------------------------------------------------------------------------------------------------------ Exposure| Target |Instr | Oper. | Aper |Spectral|Central| Optional |Num| Time | Special Number | Name |Config| Mode |or FOV |Element |Waveln.| Parameters |Exp| | Requirements ------------------------------------------------------------------------------------------------------------------------------------ 10 PC1320+4755 STIS/C ACQ F28X50L MIRROR ACQTYPE=POINT 1 14 S ONBOARD ACQ FOR 20 B CD P ------------------------------------------------------------------------------------------------------------------------------------ 20 PC1320+4755 STIS/C ACQ/PEA 52X0.2 MIRROR 1 14 S ONBOARD ACQ FOR 30, 35, B CD K 40, 45, 50 ------------------------------------------------------------------------------------------------------------------------------------ 30 PC1320+4755 STIS/N ACCUM 52X0.2 G230L 2376 1 2100 S EXPAND B UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 35 WAVE STIS/N ACCUM 52X0.2 G230L 2376 1 DEF UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 40 PC1320+4755 STIS/N ACCUM 52X0.2 G230L 2376 1 2900 S EXPAND B UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 45 WAVE STIS/N ACCUM 52X0.2 G230L 2376 1 DEF UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 50 PC1320+4755 STIS/N ACCUM 52X0.2 G230L 2376 1 2900 S EXPAND B UV-MAM A ------------------------------------------------------------------------------------------------------------------------------------ 8126( 4) - 05/11/99 10:13 - [ 13] Summary Form for Proposal 8126 Item Used in this proposal ------------------------------------------------------------------------------------------------------------------------------------ Apertures F28X50LP 52X0.2 ------------------------------------------------------------------------------------------------------------------------------------ Configurations STIS/CCD STIS/NUV-MAMA ------------------------------------------------------------------------------------------------------------------------------------ Opmodes ACQ ACQ/PEAK ACCUM ------------------------------------------------------------------------------------------------------------------------------------ Optional Parameters ACQTYPE=POINT ------------------------------------------------------------------------------------------------------------------------------------ Proposal Category GO ------------------------------------------------------------------------------------------------------------------------------------ Special Requirements GROUP 01 - 02 WITHIN 30D ONBOARD ACQ FOR 20 ONBOARD ACQ FOR 30, 35, 40, 45, 50 EXPAND EXPAND POS TARG 0, 5 EXPAND POS TARG 0,-5 GROUP 03 - 04 WITHIN 30D ONBOARD ACQ FOR 30, 35, 40, 45, 50, 55, 60 EXPAND POS TARG 0,-10 GROUP 05 - 06 WITHIN 30D GROUP 07 - 08 WITHIN 30D ------------------------------------------------------------------------------------------------------------------------------------ Spectral Elements MIRROR G230L ------------------------------------------------------------------------------------------------------------------------------------ Target Names LBQS0019-0145A WAVE LBQS0019-0145B Q0035-3518 Q0035-3520 Q0037-3545 Q0037-3544 PC1320+4755A PC1320+4755B ------------------------------------------------------------------------------------------------------------------------------------ Wavelengths 2376 ------------------------------------------------------------------------------------------------------------------------------------