Blue Sequence Research Articles

BST1047+1156: A (Failing) Ultradiffuse Tidal Dwarf in the Leo I Group

We use deep Hubble Space Telescope imaging to study the resolved stellar populations in BST1047+1156, a gas-rich, ultradiffuse dwarf galaxy found in the intragroup environment of the Leo I galaxy group. While our imaging reaches approximately two magnitudes below the tip of the red giant branch at the Leo I distance of 11 Mpc, we find no evidence for an old red giant sequence that would signal an extended star formation history for the object. Instead, we clearly detect the red and blue helium-burning sequences of its stellar populations, as well as the fainter blue main sequence, all indicative of a recent burst of star formation having taken place over the past 50–250 Myr. Comparing to isochrones for young metal-poor stellar populations, we infer this post-starburst population to be moderately metal-poor, with metallicity [M/H] in the range −1 to −1.5. The combination of a young, moderately metal-poor post starburst population and no old stars motivates a scenario in which BST1047 was recently formed during a weak burst of star formation in gas that was tidally stripped from the outskirts of the neighboring massive spiral M96. BST1047's extremely diffuse nature, lack of ongoing star formation, and disturbed H i morphology all argue that it is a transitory object, a “failing tidal dwarf” in the process of being disrupted by interactions within the Leo I group. Finally, in the environment surrounding BST1047, our imaging also reveals the old, metal-poor ([M/H] = − 1.3 ± 0.2) stellar halo of M96 at a projected radius of 50 kpc.

Specific star formation rates in the Mbh-M*,sph diagram and the evolutionary pathways of galaxies across the sSFR-M* diagram

ABSTRACT It has been suggested that the bulge-to-total stellar mass ratio or feedback from black holes (BHs), traced by the BH-to-(total stellar) mass ratio, might establish a galaxy’s specific star formation rate (sSFR). We reveal that a galaxy’s morphology – reflecting its formation history, particularly accretions and mergers – is a far better determinant of the sSFR. Consequently, we suggest that galaxy formation models which regulate the sSFR primarily through BH feedback prescriptions or bulge-regulated disc fragmentation consider acquisitions and mergers which establish the galaxy morphology. We additionally make several new observations regarding current (z ∼ 0) star-formation rates. (i) Galaxies with little to no star formation have bulges with an extensive range of stellar masses; bulge mass does not dictate presence/absence on the ‘star-forming main sequence’. (ii) The (wet merger)-built, dust-rich S0 galaxies are the ‘green valley’ bridging population between elliptical galaxies on the ‘red sequence’ and spiral galaxies on the blue star-forming main sequence. (iii) The dust-poor S0 galaxies are not on the star-forming main sequence nor in the ‘green valley’. Instead, they wait in the field for gas accretion and/or minor mergers to transform them into spiral galaxies. Mid-infrared sample selection can miss these (primordial) low dust-content and low stellar-luminosity S0 galaxies. Finally, the appearance of the quasi-triangular-shaped galaxy-assembly sequence, previously dubbed the `Triangal', which tracks the morphological evolution of galaxies, is revealed in the sSFR-(stellar mass) diagram.

Spectral sensitivities of the orchid bee Euglossa dilemma

Diurnal pollinators often rely on color cues to make decisions when visiting flowers. Orchid bees are major tropical pollinators, with most studies of their pollination behavior to date focusing on scent collection and chemical ecology. The objective of this study was to measure their spectral sensitivities to preliminarily characterize color vision in the orchid bee Euglossa dilemma and compare it to the known spectral sensitivity of other closely related bees. We compared E. dilemma's spectral sensitivities and opsin protein sequences to four closely related corbiculate bees. E. dilemma appears to have trichromatic vision, with spectral sensitivity peaks in the ultraviolet, blue, and green wavelengths (347 ± 0.957 (SE) nm, 429 ± 6.570 nm, and 537 ± 1.183 nm, respectively), similar to other measured bees. We found no differences between male and female E. dilemma visual systems despite neuroanatomical and behavioral differences reported in the literature. The lambda maxes of the ultraviolet-sensitive photoreceptors appeared to be the most conserved among the bees we compared. Meanwhile, both the lambda maxes of the blue photoreceptors and the blue opsin proteins sequences were the least conserved. Our results open up new possibilities for the study of color vision and color-mediated pollination behaviors in orchid bees.

Discovery of a Double Sequence of Blue Straggler Stars in the Core-collapsed Globular Cluster NGC 6256

We used a combination of high-resolution optical images acquired with the Hubble Space Telescope and near-IR wide-field data to investigate the stellar density profile and the population of blue straggler stars (BSSs) in the Galactic globular cluster NGC 6256, with the aim of probing its current stage of internal dynamical evolution. We found that the inner stellar density profile significantly deviates from a King model, while it is well reproduced by a steep cusp with a power-law slope α cusp = −0.89, thus implying that the cluster is currently in the post-core-collapse (PCC) phase. This is also confirmed by the very high segregation level of the BSS population measured through the parameter. We also found that the distribution of BSSs in the color–magnitude diagram is characterized by a collimated blue sequence and a red more sparse component, as already observed in three other PCC clusters. A comparison with appropriate collisional models demonstrates that the vast majority of the BSSs lying along the collimated blue sequence is consistent with a generation of coeval (1 Gyr old) stars with different masses originated by an event that highly enhanced the collisional rate of the system (i.e., the core collapse). This study confirms that the segregation level of BSSs is a powerful dynamical diagnostic also of star cluster in a very advanced stage of dynamical evolution. Moreover, it pushes forward the possibility of using the morphology of BSSs in a color–magnitude diagram as a tracer of the core-collapse and subsequent dynamical evolutionary phases.

Effect of Interchanging Red and Blue LED Irradiation Sequence on Growth of Lettuce

Light-emitting diode (LED) is commonly employed as supplementary light sources to enhance plant growth and quality. Nowadays, a combination of red (R) and blue (B) LED sources is mainly used since it can boost plant photosynthesis rate and biomass. Generally, both light sources are continuously irradiated for 16–18 hours for plant photoperiod, which may result in high electricity costs. Therefore, interchanging use of red and blue LED irradiation is introduced to reduce the use of electricity, thus minimising the operating cost. In this study, a growth chamber with red and blue LED was constructed and its intensity and power distribution were assessed. The effect of blue and red LED irradiation sequence on plant growth parameters and chlorophyll content was examined. Three light treatments over a period of 16 hours (RB16 - 16 hours constant simultaneous (R) and (B) light, R4/B4 - 4 hours interval interchanging R and B light and R8/B8 - 8 hours interval interchanging R- and B-light) were exposed to lettuce under controlled room temperature. Results revealed that the different light treatments influence lettuce plant morphology such as plant height, leaf width and leaf number. However, the results are similar for fresh and dry mass, and chlorophyll concentration. It is found that, both plant height and leaf width were the highest under R4/B4 and RB16, respectively. Such findings would be extremely valuable information on the use of interchanging LED irradiation in plant development for commercial production, resulting in optimized power consumption.

Binary Evolution and Blue Stragglers in Different Regions of the Color–Magnitude Diagrams of Globular Clusters with Different Ages

Blue stragglers (BSs) in different regions (e.g., two sequences) of the color–magnitude diagram (CMD) have been suggested to provide a strong constraint on the origin of BSs in globular clusters (GCs). However, our understanding of the locations of binary-induced BSs is incomplete, e.g., its low-luminosity boundary. By employing Eggleton’s stellar evolution code, the locations of mass-transferring (MT) BS binaries and post-mass-transfer (post-MT) BS binaries are investigated in the CMDs of GCs with different ages. The results show that post-MT BS binaries always populate the region of the CMD below the ZAMS+0.75 for GCs older than 10 Gyr and can also populate the region above the ZAMS+0.75 (the region of MT BS binaries). The low-luminosity boundary of the binary-induced BSs is located near the ZAMS in a way that is independent of the age of old GCs. The BS binaries draw a narrow sequence below the ZAMS+0.75 and cover most of the BSs in NGC 362. These results support that binary evolution can explain the appearance of BSs in different regions of the CMDs of GCs with different ages, and at least a fraction of BSs along the blue sequence could be post-MT BSs. However, the theoretical gap does not exactly correspond to the observed gap in NGC 362, and the models predict an excess of BSs below ZAMS+0.75 with respect to the observations in NGC 362. Therefore, more theoretical and observational work is needed to clarify the origin of these discrepancies.

Discovery of double BSS sequences in the old Galactic open cluster Berkeley 17

ABSTRACT Blue straggler stars (BSS) are peculiar objects which normally appear as a single broad sequence along the extension of the main sequence. Only four globular clusters (GCs) have been observed to have two distinct and parallel BSS sequences. For the first time for any open cluster (OC), we report double BSS sequences in Berkeley 17. Using the machine-learning based membership algorithm ML-MOC on Gaia EDR3 data, we identify 627 cluster members, including 21 BSS candidates out to 15 arcmin from the cluster centre. Both the BSS sequences are almost equally populated and parallel to one another in Gaia as well as in Pan-STARRS colour–magnitude diagram (CMD). We statistically confirm their presence and report that both BSS sequences are highly segregated compared to the reference population out to ∼5.5 arcmin and not segregated thereafter. The lower densities of OCs make BSS formation impossible via the collisional channel. Therefore, mass transfer seems to be the only viable channel for forming candidates of both sequences. The gap between the red and blue BSS sequences, on the other hand, is significant and presents a great opportunity to understand the connection between BSS formation and internal as well as external dynamics of the parent clusters.

A Multiwavelength View of IC 860: What Is in Action inside Quenching Galaxies * * Herschel is an ESA space observatory with science instruments provided by European-led principal investigator consortia and with important participation from NASA.

We present a multiwavelength study of IC 860, a nearby post-starburst galaxy at the early stage of transitioning from blue and star forming to red and quiescent. Optical images reveal a galaxy-wide, dusty outflow originating from a compact core. We find evidence for a multiphase outflow in the molecular and neutral gas phase from the CO position–velocity diagram and NaD absorption features. We constrain the neutral mass outflow rate to be ∼0.5 M ⊙ yr−1, and the total hydrogen mass outflow rate to be ∼12 M ⊙ yr−1. Neither outflow component seems able to escape the galaxy. We also find evidence for a recent merger in the optical images, CO spatial distribution, and kinematics, and evidence for a buried active galactic nucleus in the optical emission line ratios, mid-IR properties, and radio spectral shape. The depletion time of the molecular gas reservoir under the current star formation rate is ∼7 Gyr, indicating that the galaxy could stay at the intermediate stage between the blue and red sequence for a long time. Thus the timescales for a significant decline in star formation rate (quenching) and gas depletion are not necessarily the same. Our analysis supports the quenching picture where outflows help suppress star formation by disturbing rather than expelling the gas and shed light on possible ongoing activities in similar quenching galaxies.

Galaxy Alignments with Surrounding Structure in the Sloan Digital Sky Survey

Using data from the Sloan Digital Sky Survey Legacy Survey, we study the alignment of luminous galaxies with spectroscopic data with the surrounding larger-scale structure as defined by galaxies with only photometric data. We find that galaxies from the red sequence have a statistically significant tendency for their apparent long axes to align parallel to the projected surrounding structure. Red galaxies more luminous than the median of our sample (M r < −21.78) have a mean alignment angle 〈Φ〉 < 45°, indicating preferred parallel alignment, at a significance level >4.5σ on projected scales 0.1 Mpc < r p ≤ 7.5 Mpc. Fainter red galaxies have 〈Φ〉 < 45° at a significance level >4.3σ at scales 1 Mpc < r p < 3 Mpc. At a projected scale r p = 3.0 Mpc, the mean alignment angle decreases steadily with increasing luminosity for red galaxies with M r ≲ −22.5, reaching 〈Φ〉 = 40.°49 ± 0.°56 for the most luminous 1% (M r ∼ −23.57). Galaxies from the blue sequence show no statistically significant tendency for their axes to align with larger-scale structure, regardless of galaxy luminosity. Galaxies in higher-density regions do not show a statistically significant difference in the mean alignment angle from galaxies in lower-density regions; this holds true for the faint blue, luminous blue, faint red, and luminous red subsets.

A Linear Divider Between the Blue Sequence and Red Sequence in Color–Magnitude Space

We compute the optimal divider between the red sequence and blue sequence in the Sloan Digital Sky Survey Legacy Survey of galaxies. Within the luminosity range −18 > M r > −24, we find a good fit with a simple linear relation, u − r = 2.326–0.1305(M r + 21).

Probing red supergiant dynamics through photo-center displacements measured by Gaia

Context. Red supergiant (RSGs) are cool massive stars in a late phase of their evolution when the stellar envelope becomes fully convective. They are the brightest stars in the universe at infrared light and can be detected in galaxies far beyond the Local Group, allowing for accurate determination of chemical composition of galaxies. The study of their physical properties is extremely important for various phenomena including the final fate of massive stars as type II supernovae and gravitational wave progenitors. Aims. We explore the well-studied nearby young stellar cluster χ Per, which contains a relatively large population of RSG stars. Using Gaia EDR3 data, we find the distance of the cluster (d = 2.260 ± 0.020 kpc) from blue main sequence stars and compare with RSG parallax measurements analysing the parallax uncertainties of both groups. We then investigate the variability of the convection-related surface structure as a source for parallax measurement uncertainty. Methods. We use state-of-the-art three-dimensional radiative hydrodynamics simulations of convection with CO5BOLD and the post-processing radiative transfer code OPTIM3D to compute intensity maps in the Gaia G photometric system. We calculate the variabiltiy, as a function of time, of the intensity-weighted mean (or the photo-center) from the synthetic maps. We then select the RSG stars in the cluster and compare their uncertainty on parallaxes to the predictions of photocentre displacements. Results. The synthetic maps of RSG show extremely irregular and temporal variable surfaces due to convection-related dynamics. Consequentially, the position of the photo-center varies during Gaia measurements between 0.033 and 0.130 AU (≈1 to ≈5% of the corresponding simulation stellar radius). We argue that the variability of the convection-related surface structures accounts for a substantial part of the Gaia EDR3 parallax error of the RSG sample of χ Per. Conclusions. We suggest that the variation of the uncertainty on Gaia parallax could be exploited quantitatively using appropriate RHD simulations to extract, in a unique way, important information about the stellar dynamics and parameters of RSG stars.

From IgZ to IgT: A Call for a Common Nomenclature for Immunoglobulin Heavy Chain Genes of Ray-Finned Fish

From IgZ to IgT: A Call for a Common Nomenclature for Immunoglobulin Heavy Chain Genes of Ray-Finned Fish

Distances, extinctions, and stellar parameters for stars in SkyMapper DR3

ABSTRACT We present a Bayesian isochrone fitting machinery to derive distances, extinctions, and stellar parameters (Teff, log g, and $\rm [Fe/H]$) for stars in the SkyMapper data release 3 (DR3) survey. We complement the latter with photometry from Gaia, 2MASS, and AllWISE, in addition to priors on parallaxes and interstellar extinction. We find our results to be in agreement with smaller samples of literature values derived using spectroscopic/photometric method, with typical uncertainties of order 130 K in effective temperature and 0.2 dex in surface gravity and metallicity. We demonstrate the quality of our stellar parameters by benchmarking our results against various spectroscopic surveys. We highlight the potential that SkyMapper bears for stellar population studies showing how we are able to clearly differentiate metallicities along the Gaia red (∼−0.4 dex) and blue (∼−1.1 dex) sequences using both dwarf and giant stars.

The proper motion of Andromeda from Gaia EDR3: confirming a nearly radial orbit

Abstract We present an analysis of the proper motion of the Andromeda galaxy (M31), based on the Early Third Data Release of the Gaia mission. We use the Gaia photometry to select young blue main sequence stars, and apply several quality cuts to obtain clean samples of these tracers. After correcting the proper motion measurements for the internal rotation of the M31 disk motion, we derive an apparent motion of 52.5 ± 5.8 μas/yr with respect to the Gaia reference frame, or 61.9 ± 9.7 μas/yr after applying a zero-point correction determined from quasars within $20\deg$ from M31 and a correction from systemic biases. Accounting for the Solar reflex motion we deduce a relative velocity between Andromeda and the Milky way (in a non-rotating frame at the current location of the Sun) of 42.2 ± 39.3 km s−1 along right ascension (40.0 ± 39.3 km s−1 along galactic longitude) and −59.4 ± 30.3 km s−1 along declination (−60.9 ± 30.3 km s−1 along galactic latitude), with a total transverse velocity of Vtrans = 82.4 ± 31.2 km s−1. These values are consistent with (but more accurate than) earlier Hubble Space Telescope measurements that predict a future merger between the two galaxies. We also note a surprisingly large difference in the derived proper motion between the blue stars in M31 and samples of red stars that appear to lie in that galaxy. We propose several hypotheses to explain the discrepancy but found no clear evidence with the current data to privilege any one of them.

A bottom-heavy initial mass function for the likely-accreted blue-halo stars of the Milky Way

ABSTRACT We use Gaia DR2 to measure the initial mass function (IMF) of stars within 250 pc and masses in the range of 0.2 &amp;lt; m/M⊙ &amp;lt; 1.0, separated according to kinematics and metallicity, as determined from Gaia transverse velocity, vT, and location on the Hertzsprung–Russell diagram (HRD). The predominant thin-disc population (vT &amp;lt; 40 km s−1) has an IMF similar to traditional (e.g. Kroupa) stellar IMFs, with star numbers per mass interval dN/dm described by a broken power law, m−α, and index $\alpha _\textrm {high}=2.03^{+0.14}_{-0.05}$ above m ∼ 0.5, shallowing to $\alpha _\textrm {low}=1.34^{+0.11}_{-0.22}$ at m ≲ 0.5. Thick-disc stars (60 km s−1 &amp;lt;vT &amp;lt; 150 km s−1) and stars belonging to the ‘high-metallicity’ or ‘red-sequence’ halo (vT &amp;gt; 100 km s−1 or vT &amp;gt; 200 km s−1, and located above the isochrone on the HRD with a metallicity [M/H] &amp;gt; −0.6) have a somewhat steeper high-mass slope, $\alpha _\textrm {high}=2.35^{+0.97}_{-0.19}$ (and a similar low-mass slope $\alpha _\textrm {low}=1.14^{+0.42}_{-0.50}$). Halo stars from the ‘blue sequence’, which are characterized by low metallicity ([M/H] &amp;lt; −0.6), however, have a distinct, bottom-heavy IMF, well described by a single power law with $\alpha =1.82^{+0.17}_{-0.14}$ over most of the mass range probed. The IMF of the low-metallicity halo is reminiscent of the Salpeter-like IMF that has been measured in massive early-type galaxies, a stellar population that, like Milky Way halo stars, has a high ratio of α elements to iron, [α/Fe]. Blue-sequence stars are likely the debris from accretion by the Milky Way, ∼10 Gyr ago, of the Gaia-Enceladus dwarf galaxy, or similar events. These results hint at a distinct mode of star formation common to two ancient stellar populations – elliptical galaxies and galaxies possibly accreted early-on by ours.

SEEDisCS

We investigate how the galaxy reservoirs of molecular gas fuelling star formation are transformed while the host galaxies infall onto galaxy cluster cores. As part of the Spatially Extended ESO Distant Cluster Survey (SEEDisCS), we present CO(3-2) observations of 27 star-forming galaxies obtained with the Atacama Large Millimeter Array. These sources are located inside and around CL1411.1−1148 at z = 0.5195, within five times the cluster virial radius. These targets were selected to have stellar masses (Mstar), colours, and magnitudes similar to those of a field comparison sample at similar redshift drawn from the Plateau de Bure high-z Blue Sequence Survey (PHIBSS2). We compare the cold gas fraction (μH2 = MH2/Mstar), specific star formation rates (SFR/Mstar) and depletion timescales (tdepl = MH2/SFR) of our main-sequence galaxies to the PHIBSS2 subsample. While the most of our galaxies (63%) are consistent with PHIBSS2, the remainder fall below the relation between μH2 and Mstar of the PHIBSS2 galaxies at z ∼ 0.5. These low-μH2 galaxies are not compatible with the tail of a Gaussian distribution, hence they correspond to a new population of galaxies with normal SFRs but low gas content and low depletion times (≲1 Gyr), absent from previous surveys. We suggest that the star formation activity of these galaxies has not yet been diminished by their low fraction of cold molecular gas.

Anomalous Stellar Populations in Low-surface-brightness Galaxies

Abstract We present new Hubble Space Telescope WFC3 near-IR observations of the color–magnitude diagrams (CMDs) in two low-surface-brightness galaxies, F575-3 and F615-1, notable for having no current star formation based on a lack of Hα emission. Key features of the near-IR CMDs are resolved, such as the red giant branch (RGB), the asymptotic giant branch (AGB) region, and the top of the blue main sequence. F575-3 has the bluest RGB of any CMD in the literature, indicating an extremely low mean metallicity. F615-1 has unusually wide RGB and AGB sequences, suggesting multiple episodes of star formation from metal-poor gas, and possibly infalling material. Both galaxies have an unusual population of stars to the red of the RGB and lower in luminosity than typical AGB stars. These stars have normal optical colors but abnormal near-IR colors. We suggest that this population of stars might be analogous to local peculiar stars like Be stars with strong near-IR excesses owing to a surrounding disk of hot gas.

Specific Coordination between Zr-MOF and Phosphate-Terminated DNA Coupled with Strand Displacement for the Construction of Reusable and Ultrasensitive Aptasensor.

Electrochemical aptasensors involved in chemical labeling are often single-use and sensitivity-limited because the probes are commonly single-point labeled and irreversible. In this work, the specific coordination between Zr4+ and phosphate group (-PO43-) was employed to construct a new aptasensor that is highly sensitive and reusable, using Ochratoxin A (OTA) as the test model. The OTA binding aptamer (OBA) was hybridized with the thiolated supporting sequence (TSS) immobilized on the surface of a gold electrode. The UiO-66 with a formula of [Zr6O4(OH)4(BDC)6], one of the class of Zr metal-organic frameworks (MOFs), was then particularly grafted on the terminal of OBA through the specific coordination between Zr4+ and 5'-PO43-, i.e., the Zr-O-P coordination bond. Similarly, as much as the 5'-PO43- and 3'-methylene blue dual-labeled sequences (DLS) were further assembled on UiO-66 due to the large surface area of MOF and rich active sites of Zr4+. Owing to the specific coordination for signal amplification, the developed aptasensor shows greatly enhanced sensitivity. A wide detection range from 0.1 fM to 2.0 μM and an ultralow detection limit of 0.079 fM (S/N = 3) for OTA were obtained. Additionally, the TSS can rehybridize with a new OBA to regenerate the aptasensor but without complicated pretreatments, enabling a aptasensor that is readily reusable for OTA detection. The aptasensor was successfully applied for OTA detection in the red wine samples, demonstrating a promising prospect for food safety monitoring.

The SkyMapper-Gaia RVS view of the Gaia–Enceladus–Sausage – an investigation of the metallicity and mass of the Milky Way’s last major merger

ABSTRACT We characterize the Gaia–Enceladus–Sausage kinematic structure recently discovered in the Galactic halo using photometric metallicities from the SkyMapper survey, and kinematics from Gaia radial velocities measurements. By examining the metallicity distribution functions (MDFs) of stars binned in kinematic/action spaces, we find that the $\sqrt{J_R}$ versus Lz space allows for the cleanest selection of Gaia–Enceladus–Sausage stars with minimal contamination from disc or halo stars formed in situ or in other past mergers. Stars with $30 \le \sqrt{J_R} \le 50$ (kpc km s−1)1/2 and −500 ≤ Lz ≤ 500 kpc km s−1 have a narrow MDF centred at [Fe/H] = −1.17 dex with a dispersion of 0.34 dex. This [Fe/H] estimate is more metal-rich than literature estimates by 0.1−0.3 dex. Based on the MDFs, we find that selection of Gaia–Enceladus–Sausage stars in other kinematic/action spaces without additional population information leads to contaminated samples. The clean Gaia–Enceladus–Sausage sample selected according to our criteria is slightly retrograde and lies along the blue sequence of the high VT halo colour magnitude diagram dual sequence. Using a galaxy mass–metallicity relation derived from cosmological simulations and assuming a mean stellar age of 10 Gyr, we estimate the mass of the Gaia–Enceladus–Sausage progenitor satellite to be 108.85–9.85 M⊙, which is consistent with literature estimates based on disc dynamic and simulations. Additional information on detailed abundances and ages would be needed for a more sophisticated selection of purely Gaia–Enceladus–Sausage stars.

The Black Hole Mass–Color Relations for Early- and Late-type Galaxies: Red and Blue Sequences

Abstract The tight correlations between supermassive black hole (SMBH) mass (M BH) and the properties of the host galaxy have useful implications for our understanding of the growth of SMBHs and of the evolution of galaxies. Here, we present newly observed correlations between M BH and the host galaxy total UV−[3.6] color ( , Pearson's r = 0.6–0.7) for a sample of 67 galaxies (20 early-type galaxies and 47 late-type galaxies) with directly measured M BH in the Galaxy Evolution Explorer/S4G survey. The colors are carefully measured in a homogeneous manner using the far-UV, near-UV, and 3.6 μm magnitudes of the galaxies and their multicomponent structural decompositions in the literature. We find that more massive SMBHs are hosted by (early- and late-type) galaxies with redder colors, but the relations for the two morphological types have slopes that differ at ∼2σ level. Early-type galaxies define a red sequence in the diagrams, while late-type galaxies trace a blue sequence. Within the assumption that the specific star formation rate of a galaxy (sSFR) is well traced by L UV/L 3.6, it follows that the SMBH masses for late-type galaxies exhibit a steeper dependence on sSFR than those for early-type galaxies. The and M BH − L 3.6,tot relations for the sample galaxies reveal a comparable level of vertical scatter in the log M BH direction, approximately 5%–27% more than the vertical scatter of the M BH − σ relation. Our relations suggest different channels of SMBH growth for early- and late-type galaxies, consistent with their distinct formation and evolution scenarios. These new relations offer the prospect of estimating SMBH masses reliably using the galaxy color alone. Furthermore, we show that they are capable of estimating intermediate black hole masses in low-mass early- and late-type galaxies.