Carnegie Supernova Project-II: Using Near-infrared Spectroscopy to Determine the Location of the Outer ⁵⁶Ni in Type Ia Supernovae^∗

Type Ia supernovae (SNe Ia) are the thermonuclear explosions of at least one carbon–oxygen white dwarf (WD) in a binary system. However, the exact nature of their progenitors and critical details of their explosion physics remain open questions.

The currently favored progenitor scenarios are the single degenerate scenario, where a WD accretes material from a nondegenerate companion star such as a H/He or red giant star (Whelan & Iben 1973; Livne 1990), and the double degenerate scenario, consisting of two WDs (Iben & Tutukov 1984). Within each progenitor scenario there are different explosion mechanisms and progenitor masses. However, it is still not clear if all of these scenarios are seen in nature, and if one of them dominates the production of SNe Ia in the universe. For a recent review on SNe Ia explosion scenarios, see Livio & Mazzali (2018).

SNe Ia follow a luminosity–width relation (LWR), where brighter objects have broader light curves (Phillips 1993). Subluminous, 1991bg-like (Filippenko et al. 1992) SNe Ia are located at the faint end of the LWR (e.g., Ashall et al. 2016a), and depending on the parameter combination used, subluminous SNe Ia have been proposed to be both part of a continuous distribution from normal SNe Ia (e.g., Hoeflich et al. 2017; Ashall et al. 2018; Burns et al. 2018) and from a distinct population (e.g., Stritzinger et al. 2006; Blondin et al. 2017; Dhawan et al. 2017; Scalzo et al. 2019).

At near-infrared (NIR) wavelengths SNe Ia are nearly standard candles and suffer from less systematic effects compared to the optical (Krisciunas et al. 2004; Wood-Vasey et al. 2008; Mandel et al. 2011; Kattner et al. 2012; Burns et al. 2014; Dhawan et al. 2018; Avelino et al. 2019). As a result current SNe Ia cosmology programs such as the Carnegie Supernova Project II (CSP-II; Phillips et al. 2019) have turned their attention toward longer wavelengths.

NIR spectroscopy offers a promising way to investigate the physics of SNe Ia, as it enable us to receive light from different depths in a supernova's atmosphere at the same epoch. This means a single NIR spectrum can simultaneously probe different burning regions in an SN Ia explosion. For normal-bright SNe Ia in the NIR, by a few days past maximum light,¹⁵ there is no well-defined photosphere, and line blanketing dominates the opacity. In the region where there are lines, this opacity provides a quasi-continuum that is formed at relatively large radii. Conversely, in areas with few lines there is less opacity, enabling much deeper regions of the ejecta to be visible.

One wavelength region of interest coincides with the H-band where, between maximum light and +10 days, a complex iron-peak emission feature emerges due to allowed transitions located above the photosphere (Kirshner et al. 1973; Wheeler et al. 1998; Höflich et al. 2002; Marion et al. 2009; Hsiao et al. 2013). Previous work has found a correlation between the strength of this feature and the color-stretch parameter (Hsiao et al. 2013). Moreover, with a limited sample, Hsiao (2009) found an indication of a correlation between the velocity of this feature and light-curve shape. This iron-peak feature consists of a blend of many Fe ii/Co ii/Ni ii allowed emission lines. The Fe and Co in these epochs are produced through the radioactive decay of ⁵⁶Ni. To first order, the luminosity of a supernova is dependent on the amount of ⁵⁶Ni synthesized in the explosion, where less luminous objects produce smaller amounts of ⁵⁶Ni (e.g., Arnett 1982; Stritzinger et al. 2006; Mazzali et al. 2007).

A primary objective of the CSP-II was to obtain a large sample of NIR spectra of SN Ia (Hsiao et al. 2019). In this work, we use a subset of these spectra to examine the H-band iron-peak feature in transitional and subluminous SNe Ia. Transitional objects are a link between normal-bright SNe Ia and the subluminous, 1991bg-like population (see, e.g., Pastorello et al. 2007; Hsiao et al. 2015; Ashall et al. 2016a, 2016b; Gall et al. 2018). Transitional SNe Ia are characterized by having (i) fast declining light curves, with ${\rm{\Delta }}{m}_{15}(B)\gt 1.6$ mag,¹⁶ (ii) a secondary i-band NIR maxima that peaks after the time of B-band maximum, (iii) and no strong Ti ii absorption at 4400 Å.

Here, we suggest that the highest blue-edge velocity (v_edge) of the iron-peak feature represents the outer edge of ⁵⁶Ni in the SNe Ia explosion. In an accompanying paper (Ashall et al. 2019) we compare v_edge to explosion models, and demonstrate it is a measurement of the specific kinetic energy in SNe Ia. We also show that v_edge is a quantification of the outer ⁵⁶Ni abundance in the ejecta. v_edge measures the point in velocity space where X_Ni falls to of order 0.03–0.10. Therefore, v_edge is a direct probe of the sharp transition between the incomplete and complete Si-burning regions in the ejecta.

Finally, we note that although the light-curve decline-rate parameter—${\rm{\Delta }}{m}_{15}(B)$—has successfully been used to calibrate the luminosity of SNe Ia, it is degenerate when dealing with subluminous and transitional objects. This is because, for the least luminous SNe Ia, the inflection point in the B-band light curve occurs prior to +15 days (Phillips 2012). Therefore, throughout the following work we characterize the properties of SNe Ia light curves with the color-stretch s_BV parameter. s_BV is a dimensionless parameter defined as the time difference between B-band maximum and the reddest point in the B − V color curve divided by 30 days, where typical SNe Ia have s_BV ≈ 1 (Burns et al. 2014).

The selection criteria for the sample were set such that the SNe Ia were transitional or subluminous (i.e., they had s_BV < 0.8), and have at least one NIR spectrum, between +5 and +20 days, as these are the phases when it is predicted that the Fe/Co/Ni emission occurs (Marion et al. 2009), and is when the H-band break appears in the spectroscopic data. There were 12 SNe Ia that met these criteria from the CSP-II data set. The subluminous SN 1999by (s_BV = 0.44 (Höflich et al. 2002) and the normal SN 2011fe (s_BV = 0.95), SN 2014J (s_BV = 1.05), and ASASSN-14lp (s_BV = 1.084) (Hsiao et al. 2013; Pereira et al. 2013; Marion et al. 2015) were also used in the analysis. The basic properties of these SNe are presented in Table 1.

Table 1.  The Properties of the SNe Ia and a log of the NIR and Optical Spectral Observations

SN	z	sBV	${\rm{\Delta }}{m}_{15}(B)$	TBmaxa	Tspecb	Phasec	vedge	Instrument/Telescope
			(mag)	(JD−2,450,000)	(JD−2,450,000)	(days)	(km s−1)
NIR
ASASSN-14lp	0.005	1.08 ± 0.05	0.85 ± 0.07	57015.3	57020.3	+5.0	−14,700 ± 100	F2/Gemini-S
					57025.3	+10.0	−13,700 ± 100	F2/Gemini-S
SN 2014J	0.0001	1.05 ± 0.086	1.05 ± 0.05	56689.75	56694.95	+5.2	−14,100 ± 200	Mt Abu
					56695.78	+6.0	−14,100 ± 100	Mt Abu (1)
					56696.93	+7.1	−13,900 ± 100	Mt Abu (1)
					56697.92	+8.1	−13,800 ± 100	Mt Abu (1)
					56699.84	+10.0	−13,400 ± 100	Mt Abu (1)
SN 2011fe	0.001	0.95 ± 0.01	1.21 ± 0.05	55813.93	55822.13	+8.2	−13,800 ± 600	GNIRS/Gemini-N
					55826.22	+12.3	−13,500 ± 100	GNIRS/Gemini-N
					55831.21	+17.3	−13,300 ± 100	GNIRS/Gemini-N
SN 2011jh	0.008	0.80 ± 0.01	1.46 ± 0.01	55931.06	55941.84	+10.69*	−13,300 ± 400	FIRE/Baade
SN 2013aj	0.009	0.78 ± 0.01	1.47 ± 0.01	56361.37	56371.72	+10.25*	−13,600 ± 300	FIRE/Baade
					56376.81	+15.30*	−12,300 ± 300	FIRE/Baade
PS1-14ra	0.028	0.77 ± 0.01	⋯	56724.54	56734.84	+10.01*	−13,000 ± 900	FIRE/Baade
					56741.82	+16.81*	−10,900 ± 2200	FIRE/Baade
ASASSN-15aj	0.011	0.76 ± 0.01	1.44 ± 0.02	57035.46	57050.64	+15.01*	−12,100 ± 500	FIRE/Baade
PSN-171d	0.020	0.71 ± 0.01	1.54 ± 0.02	57070.43	57088.82	+18.03*	−6700 ± 2000	FIRE/Baade
SNhunt281e	0.004	0.68 ± 0.01	1.56 ± 0.03	57112.67	57119.79	+7.09*	−12,200 ± 300	FIRE/Baade
					57124.72	+12.00*	−12,200 ± 900	FIRE/Baade
					57128.41	+15.74*	−7100 ± 100	GNIRS/Gemini-N
					57131.28	+18.71*	−7200 ± 100	Spex/IRTF
LSQ14ajnf	0.021	0.64 ± 0.01	1.74 ± 0.02	56734.73	56741.70	+6.83*	−12,400 ± 1200	FIRE/Baade
SN 2011iv	0.006	0.64 ± 0.01	1.74 ± 0.01	55906.08	55911.70	+5.58	−13,200 ± 200	FIRE/Baade
					55913.68	+7.55	−12,800 ± 200	FIRE/Baade
					55915.7	+9.60	−12,500 ± 200	SOFI/NTT
					55916.75	+10.60	−12,900 ± 200	FIRE/Baade
					55924.6	+18.50	−6300 ± 200	ISAAC/VLT
iPTF13ebh	0.013	0.61 ± 0.01	1.76 ± 0.02	56623.29	56630.0	+6.71	−12,100 ± 100	GNIRS/Gemini-N
					56635.58	+12.12	−10,600 ± 1800	FIRE/Baade
					56640.56	+17.04	−7200 ± 1000	FIRE/Baade
ASASSN-15ga	0.007	0.50 ± 0.03	2.13 ± 0.04	57115.88	57124.68	+8.74*	−6500 ± 1500	FIRE/Baade
SN 2015bo	0.016	0.47 ± 0.01	1.85 ± 0.02	57076.02	57088.86	+12.63*	−7000 ± 1300	FIRE/Baade
SN 2013ay	0.016	0.46 ± 0.05	⋯	56375.41	56383.84	+8.30*	−7700 ± 600	FIRE/Baade
					56385.91	+10.33*	−7800 ± 700	FIRE/Baade
SN 1999by	0.002	0.44 ± 0.01	1.90 ± 0.05	51308	51316	+8	−7600 ± 300	TIFKAM/Hiltner (2)
					51319	+11	−5500 ± 200	TIFKAM/Hiltner
					51322	+14	−5000 ± 300	TIFKAM/Hiltner
Optical
ASASSN-14lp	0.005	1.08 ± 0.05	0.85 ± 0.07	57015.3	57011	−4	⋯	FLWO-1.5 m / FAST (3)
SN 2014J	0.0001	1.05 ± 0.086	1.05 ± 0.05	56689.75	56692	+2	⋯	Frodospec/LT (4)
SN 2011fe	0.001	0.95 ± 0.01	1.21 ± 0.05	55813.93	55814	+0	⋯	SNIFS/UH 2.2m (5)
SN 2011jh	0.008	0.80 ± 0.01	1.46 ± 0.01	55931.06	55927	−4	⋯	B& C/Du Pont (6)
SN 2013aj	0.009	0.78 ± 0.01	1.47 ± 0.01	56361.37	56356	−5	⋯	EFOSC/NTT (7)
PS1-14ra	0.028	0.77 ± 0.01	⋯	56724.54	56728	+3	⋯	ALFOSC/NOT (6)
ASASSN-15aj	0.011	0.76 ± 0.01	1.44 ± 0.02	57035.46	57035	+0	⋯	MIKE Clay (6)
PSN-171d	0.020	0.71 ± 0.01	1.54 ± 0.02	57070.43	57068	−2	⋯	ALFOSC/NOT (6)
SNhunt281e	0.004	0.68 ± 0.01	1.56 ± 0.03	57112.67	57108	−5	⋯	ALFOSC/NOT (6)
LSQ14ajnf	0.021	0.64 ± 0.01	1.74 ± 0.02	56734.73	56729	−6	⋯	ALFOSC/NOT (6)
SN 2011iv	0.006	0.64 ± 0.01	1.74 ± 0.01	55906.08	55907	+1	⋯	STIS/HST (8)
iPTF13ebh	0.013	0.61 ± 0.01	1.76 ± 0.02	56623.29	56623	+0	⋯	DBSP/Palomar200 (9)
ASASSN-15ga	0.007	0.50 ± 0.03	2.13 ± 0.04	57115.88	57121	+5	⋯	ALFOSC/NOT (6)
SN 2015bo	0.016	0.47 ± 0.01	1.85 ± 0.02	57076.02	57079	+3	⋯	B& C/Du Pont (6)
SN 1999by	0.002	0.44 ± 0.01	1.90 ± 0.05	51308	51303	−5	⋯	FAST/FLWO (10)

Notes. The ${\rm{\Delta }}{m}_{15}(B)$ values were obtained from a direct spline fit to the data, and the values of s_BV were obtained from the best fits from SNooPy.

^aTime B-band maximum, calculated from the CSP-II light curves. ^bTime of spectral observation. ^cPhase of spectra in rest frame relative to B-band maximum. ^dJ13471211-2422171. ^eSN 2015bp. ^fSN 2014ah.

References. (1) Marion et al. (2015); (2) Höflich et al. (2002); (3) Shappee et al. (2016); (4) Ashall et al. (2014); (5) Pereira et al. (2013); (6) N. Morrell et al. (2019, in preparation); (7) Smartt et al. (2015); (8) Gall et al. (2018); (9) Hsiao et al. (2015); (10) Garnavich et al. (2004).

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Optical spectra near maximum light of our sample (eight of which are unpublished) are plotted in Figure 1. A summary of the optical spectra can be found in Table 1. The three SNe Ia plotted in red show the typical characteristic of subluminous SNe Ia, a strong Ti ii absorption feature at ∼4400 Å. The other SNe Ia have a higher ionization state and are classical transitional objects, except for SN 2011fe, SN 2014J, and ASASSN-14lp which are normal-bright SNe Ia. We note that SN 2013ay was classified from an NIR spectrum (Hsiao et al. 2013), has a light-curve shape consistent with a subluminous SNe Ia and an s_BV = 0.46 ± 0.05, but does not have optical spectra. The unpublished CSP-II photometry of all the supernovae was checked, and the SNe Ia that were spectroscopically subluminous events were found to have small, but barely visible, secondary i-band maximum. Due to a lack of premaximum light-curve coverage, for the subluminous SNe Ia it was not possible to determine the i-band maximum relative to the B-band, except for SN 2015bo, which peaked in the i band before the B-band.

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There are 37 NIR spectra of the 16 SNe Ia in the sample, 18 of which are unpublished (see Table 1 for details). Most of the spectra were observed with the FIRE spectrograph on the Magellan Baade telescope at Las Campanas Observatory, the other unpublished spectra were observed with SpeX on the NASA Infrared Telescope Facility (IRTF), Gemini Near-InfraRed Spectrograph (GNIRS) on Gemini-North, and FLAMINGOS-2 on Gemini-South. The spectra were reduced and corrected for telluric features via the procedure described by Hsiao et al. (2019).

The full sample of the NIR spectra is plotted in Figure 2. Each spectrum is corrected to the rest-frame, labeled with the appropriate SN name and rest-frame time relative to maximum. The figure shows only the H-band region of each spectrum.¹⁷

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Here we describe our method to measure v_edge. As demonstrated in Figure 3, v_edge was measured by fitting the minimum of the region blueward of the iron-peak emission feature with a Gaussian profile. The fit is weighted by the observational flux uncertainty. The data were fitted over a ∼0.05 μm range around a central value, illustrated by the red lines in Figure 3. The continuum is defined as a straight line connecting the end points in this range and removed before the fit. The Gaussian fit was iterated, using the previous minimum of the Gaussian as the central point in the new fit, until convergence was met. This was done to ensure the continuum was properly removed. Convergence usually required ∼5 iterations. We also fit the data with a Moffat function. Using the Bayesian information criterion, and Akaike information criterion, it was found that a Gaussian function models the profile better than a Moffat function.

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An accompanying uncertainty to our best-fit value of v_edge was determined by producing 100 realizations on a smoothed spectrum with noise added in at each pixel using a normal distribution with the standard deviation of the Gaussian matching the observed flux error, denoted by the light gray error region in the left panel of Figure 3. The flux errors of the FIRE spectra come from the standard deviation in flux of the multiple exposures necessary in NIR observations (Hsiao et al. 2019). This newly constructed spectrum was then measured over the same region and with the same fitting technique as the observed input spectrum. This was done for each realization to create an array of 100 velocity measurements for the given feature whose standard deviation was taken as the measurement error of v_edge. If no error spectrum was available from the observations, an array of values was produced through subtracting the smoothed spectrum and the observations. The absolute value of these subtracted values were smoothed to generate a noise trend. This noise trend was used as a representation of the mean noise on the spectra and sampled back onto the smoothed spectra to produce another realization of the observed spectra. For each of the 100 realizations of the Gaussian fit discussed above, a different amount of noise was sampled from the noise trend back onto the smoothed spectra.

The iron-peak emission region is a multiplet of many allowed Fe/Co/Ni lines and not from an individual transition. As a result, the different components are sensitive to density and temperature, hence the ionization and excitation state in the center of the feature can differ. However, the Doppler shift of the highest energy (bluest edge) component is not sensitive to density and temperature. This is because it is a result of atomic physics. Therefore we use the outer edge of the feature to measure velocities, as this is a stable measurement. In this work we adopt 1.57 μm as the rest wavelength of the feature. This value was obtained by checking for the strongest lines from non-LTE radiation transport models of normal and subluminous SNe Ia (Höflich et al. 2002; Hoeflich et al. 2017). However, if the rest wavelength of this feature were to be altered, it would just cause a systematic shift in the values and not change the trend.

Using the method described above, v_edge was measured for each of the NIR spectra, and the results are presented in the top panel of Figure 4. Inspection of the measurements reveals that v_edge decreases over time for the majority of objects. The normal-bright ASASSN-14lp exhibits the highest velocities, reaching −14,700 ± 100 km s⁻¹ on +5.2 days and later −13,700 ± 100 km s⁻¹ on +10.0 days. Transitional objects exhibit slightly lower values of v_edge, which then decrease rapidly. For example, SN 2011iv (Ashall et al. 2018; Gall et al. 2018) extends from v_edge = −13,200 ± 200 km s⁻¹ at +5.6 days down to −6300 ± 200 km s⁻¹ by +10 days. The least luminous SNe Ia have the lowest values of v_edge, clustering around −6000 km s⁻¹. At +8 days SN 1999by has a v_edge of −7600 ± 300 km s⁻¹ and by +14 days it drops to −5000 ± 300 km s⁻¹.

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SNe Ia with a v_edge of ∼−10,000 km s⁻¹ appear to be rare. However, SN 2011iv, SNhunt281, and iPTF13ebh are the only objects that rapidly drop over the time period examined. For example, iPTF13ebh exhibits a v_edge of −10,600 ± 1800 km s⁻¹ at +12.12 days, but by +17.04 days it drops to −7200 ±1000 km s⁻¹.

In the bottom panel of Figure 4, we have plotted v_edge as a function of the color-stretch parameter s_BV. The points from the spectra at +10 ± 3 days were plotted because at later times the corresponding layers may become optically thin. Objects exhibiting larger s_BV values are found to also exhibit higher values of v_edge. v_edge was found to range from ∼−14,000 km s⁻¹ for normal-bright SNe Ia, to −10,500 km s⁻¹ for transitional SNe Ia, and down to ∼−5000 km s⁻¹ for subluminous SNe Ia. The correlation between s_BV and v_edge implies v_edge is also correlated with the peak luminosity of the SNe Ia, and hence the amount of ⁵⁶Ni produced during the explosion.

From our sample here it is not possible to rule out that there is bimodality in the data, where the subluminous SNe Ia cover a larger range in v_edge than the normal-bright SNe. However, photometric properties of SNe Ia, such as those from CSP-I, show a continuous distribution from normal to subluminous SNe Ia (Burns et al. 2018). This implies that the possible bimodal distribution seen in this work is produced by a small sample size, and the fact that transitional SNe Ia are rare. A Pearson correlation test of the points in the bottom panel of Figure 4 produced a correlation coefficient of −0.86.

A measure of v_edge provides a constraint on the outer ⁵⁶Ni distribution in the ejecta. This is because the Fe/Co/Ni emission region is located at large radii in the SN atmosphere, is an isolated multiplet, and is not contaminated by lines from other elements. Furthermore, the highest energy Doppler shift of this region will correspond to the edge of the highest velocity emission, which is a measurement of the outer ⁵⁶Ni. v_edge is therefore a valuable tool to analyze the explosion physics of SNe Ia. For example, measuring v_edge for a large sample of SNe will probe the mixing of ⁵⁶Ni in the ejecta.

v_edge is a model-independent measurement, and a diagnostic of the location between the complete and incomplete Si-burning regions. It provides an indication of the effectiveness of the burning in the ejecta. Those objects that are brighter, and produce more ⁵⁶Ni, have experienced more effective burning. The exact details of this will be explored in an accompanying paper with respect to explosion models (Ashall et al. 2019). However, the results here are consistent with those found through nebular phase spectral modeling by Mazzali et al. (1998) who showed that less luminous objects have ⁵⁶Ni located at lower velocities. A similar result was also found by Botyánszki & Kasen (2017) who demonstrate, using nebular phase modeling, that a larger ⁵⁶Ni mass (and therefore SN luminosity) produces broader Fe lines in the ejecta.

Our results indicate that ⁵⁶Ni is located at lower velocities for less luminous SNe Ia, and may argue against very low-mass explosions (less than ∼0.9M_⊙) for the subluminous SNe Ia. This is because, for the same ⁵⁶Ni mass, these very low-mass explosions tend to have the ⁵⁶Ni located at higher velocities compared to M_Ch explosions (e.g., Sim et al. 2010; Blondin et al. 2018). Finally, the fact that we see a relatively smooth distribution in v_edge as a function of light-curve shape implies that at least some SNe Ia at the faint end of the luminosity–width relationship may have a similar explosion mechanism to normal SNe Ia.

We thank our many colleagues for fruitful discussions, as well as Josh Simon, Povilas Palunas, and Mansi Kasliwal for providing telescope time. The work presented here has been supported in part by NSF awards AST-1008343 and AST-1613426 (PI: M.M.P.), AST-1613472 (PI: E.Y.H.), AST-1715133 (PI: P.H.), AST- 16113455 (PI: N.B.S.) and in part by a Sapere Aude Level II grant (PI: M.D. Stritzinger) from the Danish National Research Foundation (DFF). M.D. Stritzinger and S.H. are generously supported by a research grant (13261) from the VILLUM FONDEN. M.D. Stritzinger and E.B. acknowledge support from the Aarhus University Research Fund (AUFF) for a Sabbatical research grant. E.B. acknowledges partial support from NASA grant NNX16AB25G. Research by D.J.S. is supported by NSF grants AST-1821967, 1821987, 1813708, and 1813466. We thank the Mitchell Institute for Fundamental Physics and Astronomy for partial support. Based on observations obtained at the Gemini Observatory under program GS-2015A-Q-5 (PI: D.J.S.). Gemini is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the NSF (United States), the National Research Council (Canada), CONICYT (Chile), Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina), and Ministério da Ciência, Tecnologia e Inovação (Brazil). D.J.S. is a visiting Astronomer at the Infrared Telescope Facility, which is operated by the University of Hawaii under contract NNH14CK55B with the National Aeronautics and Space Administration. Based in part on observations made with the Nordic Optical Telescope (P49-017, P50-015, and P51-006; PI: M.D. Stritzinger), operated by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque de los Muchachos, La Palma, Spain, of the Instituto de Astrofisica de Canarias.

Facilities: Magellan: Baade (FIRE near-infrared echellette) - Magellan I Walter Baade Telescope, Magellan: Clay (Magellan Inamori Kyocera Echelle) - , du Pont (Boller & Chivens spectrograph) - , Gemini:North (GNIRS near-infrared spectrograph) - , VLT (ISAAC) - , NTT (EFOSC) - , IRTF (SpeX near-infrared spectrograph) - , Hale (DBSP) - , Hiltner (TIFKAM) - , NOT (ALFOSC) - , UH:2.2m (SNIFS) - , FLWO:1.5m (FAST) - , HST (STIS) - , La Silla-QUEST - - .