Wavelength Calibration of the Hamilton Echelle Spectrograph

Pakhomov, Yu. V.; Zhao, Gang

doi:10.1088/0004-6256/146/4/97

Cited by 13 publications

(12 citation statements)

References 8 publications

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“…1 for tantalum -a = 17.5 ± 0.1, b = 1.16 ± 0.03, for thorium -a = 19.3 ± 0.1, b = 1.16 ± 0.05. Hence, the obtained values of the gas temperature are, respectively, 3120 ± 60 K and 3130 ± 90 K. The resulting temperature is close to the value of 3200 ± 150 K, found by Pakhomov & Zhao (2013) for the other lamp of the Hamilton spectrograph, as it is expected because the lamps are operated at the same conditions.…”

Section: The Estimate Of Gas Temperaturesupporting

confidence: 86%

“…Figure 4 shows the deviations of the centers of the measured lines from the Table values for different echelle orders. The mean square error of calibration of entire spectrum comprised 0.006Å, like in the case of titanium-argon lamp (Pakhomov & Zhao 2013), but for the range 4000-7000Å the accuracy was higher -up to 0.002-0.003Å, while now it is 0.005-0.006Å, wherein some of the lines have deviations exceeding 0.01Å. This may be due to the fact that the tantalum has an odd number in the periodic table, is subject to the effect of hyperfine splitting of atomic levels.…”

Section: Discussionmentioning

confidence: 99%

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A list of tantalum lines for the wavelength calibration of the Hamilton echelle spectrograph

Pakhomov

2015

Astron. Rep.

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We present solution of the problem of wavelength calibration for Hamilton Echelle spectrograph using hollow cathode lamp, which was operated at Lick Observatory Shane telescope before June 9, 2011. The spectrum of the lamp claimed to be thoriumargon, contains, in addition to the lines of thorium and argon, a number of the unrecognized lines identified by us with tantalum. Using atomic data for measured lines of tantalum and thorium, we estimated the temperature of the gas in the lamp as T = 3120 ± 60 K. From the atomic line database VALD3 we selected all lines of TaI and TaII which can be seen in the spectrum of the lamp and compiled a list for the use in the processing of spectral observations. We note a limitation of the accuracy of calibration due to the influence of the hyperfine line splitting.

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Section: The Estimate Of Gas Temperaturesupporting

confidence: 86%

Section: Discussionmentioning

confidence: 99%

A list of tantalum lines for the wavelength calibration of the Hamilton echelle spectrograph

Pakhomov

2015

Astron. Rep.

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“…74 1 . Briefly, the spectral images were bias-subtracted, flat-fielded, extracted, and finally wavelength-calibrated with TiAr arclamp spectra (see Pakhomov & Zhao 2013).…”

Section: Lick Shane 3 M Hamilton Echellementioning

confidence: 99%

Is the Young Star RZ Piscium Consuming Its Own (Planetary) Offspring?

Punzi

Kastner

Melis

et al. 2017

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The erratically variable star RZ Piscium (RZ Psc) displays extreme optical dropout events and strikingly large excess infrared emission. To ascertain the evolutionary status of this intriguing star, we obtained observations of RZ Psc with the European Space Agency's X-ray Multi-Mirror Mission (XMM-Newton), as well as high-resolution optical spectroscopy with the Hamilton Echelle on the Lick Shane 3 m telescope and with HIRES on the Keck I 10 m telescope. The optical spectroscopy data demonstrate that RZ Psc is a pre-main sequence star with an effective temperature of 5600 ± 75 K and log g of 4.35 ± 0.10. The ratio of X-ray to bolometric luminosity, log L X /L bol , lies in the range −3.7 to −3.2, consistent with ratios typical of young, solar-mass stars, thereby providing strong support for the young-star status of RZ Psc. The Li absorption line strength of RZ Psc suggests an age in the range 30-50 Myr, which in turn implies RZ Psc lies at a distance of ∼170 pc. Adopting this estimated distance, we find the Galactic space velocity of RZ Psc to be similar to the space velocities of stars in young moving groups near the Sun. Optical spectral features indicative of activity and/or circumstellar material are present in our spectra over multiple epochs, which provide evidence for the presence of a significant mass of circumstellar gas associated with RZ Psc. We suggest that the destruction of one or more massive orbiting bodies has recently occurred within 1 au of the star, and we are viewing the aftermath of such an event along the plane of the orbiting debris. star expanded to become a red giant. Melis (2009) chose to call such dusty, first ascent giant stars "Phoenix Giants" because of their similarities to T Tauri stars (specifically, high Li abundance and strong infrared excess; Potravnov et al. 2014b). Furthermore, the strong IR excess associated with RZ Psc (L IR /L bol ∼ 8%, de Wit et al. 2013) would be very peculiar if the star is as old as ∼25 Myr.

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“…All spectra were bias-corrected and flat-fielded, and cosmic ray hits were removed. ThAr (Coralie, Hermes) and TiAr (Pakhomov & Zhao 2013, Hamilton) lamps were used for wavelength calibration.…”

Section: Description Of Observationsmentioning

confidence: 99%

Vetting Galactic Leavitt Law Calibrators Using Radial Velocities: On the Variability, Binarity, and Possible Parallax Error of 19 Long-Period Cepheids

Anderson

Casertano

Riess

et al. 2016

ApJS

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We investigate the radial velocity (RV) variability and spectroscopic binarity of 19 Galactic long-period (P puls 10 d) classical Cepheid variable stars whose trigonometric parallaxes are being measured using the Hubble Space Telescope and Gaia. Our primary objective is to constrain possible parallax error due to undetected orbital motion. Using > 1600 high-precision RVs measured between 2011 and 2016, we find no indication of orbital motion on 5 yr timescales for 18 Cepheids and determine upper limits on allowed configurations for a range of input orbital periods. The results constrain the unsigned parallax error due to orbital motion to < 2 % for 16 stars, and < 4 % for 18. We improve the orbital solution of the known binary YZ Carinae and show that the astrometric model must take into account orbital motion to avoid significant error (∼ ±100 µarcsec). We further investigate longtimescale (P orb > 10 yr) variations in pulsation-averaged velocity v γ via a template fitting approach using both new and literature RVs. We discover the spectroscopic binarity of XZ Car and CD Cyg, find first tentative evidence for AQ Car, and reveal KN Cen's orbital signature. Further (mostly tentative) evidence of time-variable v γ is found for SS CMa, VY Car, SZ Cyg, and X Pup. We briefly discuss considerations regarding a vetting process of Galactic Leavitt law calibrators and show that light contributions by companions are insignificant for most distance scale applications.

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Wavelength Calibration of the Hamilton Echelle Spectrograph

Cited by 13 publications

References 8 publications

A list of tantalum lines for the wavelength calibration of the Hamilton echelle spectrograph

A list of tantalum lines for the wavelength calibration of the Hamilton echelle spectrograph

Is the Young Star RZ Piscium Consuming Its Own (Planetary) Offspring?

Vetting Galactic Leavitt Law Calibrators Using Radial Velocities: On the Variability, Binarity, and Possible Parallax Error of 19 Long-Period Cepheids

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